# AC 20-48: Practice Guide for Decontaminating Aircraft - Type: Advisory circular (guidance, not mandatory unless a rule or AD requires it) - Status: Historical - Approved: May 5, 1966 - Family: AC 20-48 - Pages: 26 - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/D2641320BFD46E09862569B500769378.0001 - Page: https://openairdocs.org/ac/20-48 ## Versions - AC 20-48 (Historical), approved May 5, 1966 ## Text ### Page 1 AC 20-48 **PRACTICE GUIDE FOR** **DECONTAMINATING AIRCRAFT** FEDERAL AVIATION AGENCY Flight Standards Service Washington, O.C. 20553 ### Page 2 Federal Aviation Agency AC NO: 20--48 AIRCRAFT EFFECTIVE : 1966 SUBJECT: PRACTICE GUIDE FOR DECONTAMINATING AIRCRAFT **1. PURPOSE.** This publication is a guide to be used by groups or emergency readiness teams in the civil avi­ ation industry for organizing and conducting practice exercises in aircraft decontamination. **2. REFERENCE.** It is recommended that this guide be used in conjunction with the FAA publication, "Radio­ logical Protection and Decontamination of Civil Aircraft," Flight Standards Service (November 1962), for sale by Superintendent of Docwnents, U.S. Government Printing Office, Washington, D.C. 20402 (price $.65). This pµblication offers additional information to be used under actual conditions. **3. HOW TO OBT-AIN ADDITIONAL COPIES.** Additional copies of this guide can be obtain­ ed free of charge by requesting AC 20--48 from: Federal Aviation Agency Printing Branch, HQ--438 Washington, D.C. 20553 **4. BACKGROUND.** The information in this publication is the re­ sult of extensive testing in actual aircraft de­ contamination exercise operations to determine practical methods and procedures. During the tests, inadequate techniques were eliminated and only the effective and practical exercise procedures were selected for inclusion. The con­ tents of this guide originated in the FAA Central Region Defense Readiness Office and were reviewed by the Atomic Energy Com­ mission for technical and procedural accuracy. **5. USE OF PUBLICATION.** While it is impossible to write a set of pro­ cedures that will suit all emergency conditions, this guide includes the fundamental processes for the decontamination of aircraft exposed to radiation (fallout) . It is recommended that the basic principles be mastered before attempting advanced and complex situations. Every effort was made to keep the procedures simple, yet practical. and effective. The procedures contain­ ed in this publication may require modification in the case of actual fallout, since specific pro­ cedures would not be suited to all situations. An active and interested recovery team should be able to complete a successful exercise by follow­ ing the steps outlined in Chapters 1 and 2. These chapters are to be used by the team group lead­ ers as a checklist to avoid omissions or inappro­ priate sequence of operations. Chapter 3 offers suggestions for guiding the team in evaluating a completed practice exercise. Test exercises re­ vealed that working practice groups who con­ ducted three or four of these exercises became ### Page 3 adept in detecting their errors and were capable of making the necessary corrections to improve their methods or techniques for future actions. Appendix I provides information on the working equipment required and suggests methods for substitutions if necessary. **6. EXPERIENCE.** While it is desirable for all participants in one of these exercises to have some prior basic train­ ing in radiation, this cannot be expected in all cases. However, since the more technical aspects of the work involve a knowledge of radiation, the use of radiation instruments, calculating dosages, stay times, etc., it will be necessary to have at least one person in the group qualified to direct the monitoring operations. If such a person is not available within the group, he may be recruited elsewhere. There are qualified peo­ ple in each agency listed in Appendix I as sources where radiation detection instruments may be borrowed. Your local Civil Defense Director will be able to recommend a qualified person, either to act as your monitoring team leader, or to instruct your own team leader sufficiently to qualify him for the job. **7. PARTICIPANTS.** This manual is prepared primarily for general aviation personnel; however, it may be of use to other groups, such as the civil air carriers, in developing their own techniques and methods for decontamination of large aircraft . Both men and women are encouraged to participate ­ pilots, mechanics, clerks, airport employees, etc., organized groups such as CAP Squadrons, local flying clubs, flying farmer units, fixed-base op­ erators, and maintenance and repair stations. In fact, any group or organization operating an aircraft should complete this training. 8. PROFICIENCY Decontamination work is comparatively new at this time and very few people have acquired proficiency; however, it can be self-taught. It is assumed that you will make mistakes during the initial exercises, but this is normal. You will learn by doing. A lively, serious "critique" period after each exercise is the key to improve­ ment in each successive exercise. SPEED IS NOT IMPORTANT during training exercises in learning decontamination work. Your PRI­ MARY concern is (a) to learn how to do the job with a MINIMUM EXPOSURE of personnel to radiation, and (b) to remove as much of the contamination matter as possible from the air­ craft. In fact, most errors are the result of try­ ing to hurry through these procedures. The in­ structions in the following chapters will be most helpful in performing your practice exercise if taken in the order or sequence given. C. w. wALKER, Director Flight St:andards Service ### Page 4 ACKNOWLEDGEMENT We wish to thank the many people who so willingly gave their time and energy to the work of field testing the procedures necessary for the develop~ ment of this guide. We are also grateful to numerous individuals whose ad~ vfoe and suggestions were most helpful. Although space will not permit a complete list of the individuals involved, the following is a list of organizations which either participated as an entire unit or were represented by some of their members : 9502nd Air Force Reserve Recovery Squadron at Rockford, lliinois. Rockford, Illinois, C.A.P. Evanston, Illinois, Civil Defense Office. Fort Sheridan, Illinois, Defense Readiness Staff. 9536th AFRR Squadron at Des Moines, Iowa. 9547th AFRR Squadron at St. Louis, Missouri. Rockford, Illinois, Civil Defense Office. Greater Rockford Airport Management and Staff. Illinois Wing Headquarters, C.A.P. Missouri Wing Headquarters, C.A.P. Headquarters 8581st AFRR Group at Kansas City, Missouri. 9544th AFRR Squadron at Kansas City, Missouri. 9543rd AFRR Squadron at Kansas City, Missouri. FAA Tower and FSS Personnel at Rockford, Illinois. ### Page 5 AC 20-48 Page i 1966 TABLE OF CONTENTS Chapter I. HOW TO PLAN AND PREPARE AN EXERCISE Paragraph Page 1. Starting point … 1 2. Minimum organization … 1 3. Equipment … 1 4. Choosing an area … 1 5. Planning area utilization … 2 6. Setting up a problem … 2 7. Setting exercise time and date … 3 8. Pre-exercise training … 3 Chapter II. HOW TO CONDUCT THE EXERCISE **PHASE I** 9. Assembly … 7 10. Security personnel … 7 11. Equipment … 7 12. Clothing … 7 13. Final briefing … 7 14. Dress out … 7 15. Take stations … 8 16. Monitor "hot" area … 8 17. Calculate area radiation … 9 18. Post security … 9 19. Monitors - control point … 9 20. Contamination of aircraft … 10 **PHASE II** 21. Move aircraft into position … 11 22. Position monitor … 11 23. Monitor pilot … 11 24. Monitor aircraft … 11 25. Calculate the stay time … 12 PHASE Ill 26. Fir st scrubdown … 12 27. Clean personnel and washrack … 13 28. Remonitor aircraft … 13 29. Determine if second scrubd own needed … 13 30. Second scrubd own … 13 31. Recheck by monitor s … 13 32. Removal of aircraft … 13 ### Page 6 .... ii A.C 20-48,~ TABLE OF CONTENTS-Continued PHASE IV Parag'l'aph Pa.ge 33. Monit.or each vehicle and unit of equipment . . • . . • … 13 34. Monit.or personnel . . . . . . . . . . . . . . . . . . . . . . . . . . . . • … 14 35. Removal of protective clothing … 14 36. Final monitoring check … 14 37. Read individual dosimeters … 14 Chapter Ill. CRITIQUE OF THE EXERCISE 38. Critique session … 15 APPENDIX I. Equipment … 17 APPENDIX II. Glossary … 21 ### Page 7 AC 20-48 Page 1 1966 Chapter i. HOW TO PLAN AND PREPARE AN EXERCISE 1. STARTING POINT. Enlist a group of 6 to 20 or more interested persons and have all partici­ pants read this guide. This can be done prior to or at the first meeting of the group. **2. MINIMUM ORGANIZATION.** a. The Group Leader (one) will direct the overall planning, preparation, execution, and final critique of the exercise. During the actual exercise, the group leader should locate his C.P. or command post (see area map on page 5) in a position where he can observe all of the activities. He will direct the team leaders to perform each step of the exercise at the appro­ priate time. The group leader will make the decisions for the group that cannot be deter­ mined by team leaders. He will work closely with his monitoring team leader, who will keep him advised of the radiation situation, enabling him to make command decisions involving the safety of personnel and the extent or degree of decontamination required. The group leader should have a positive knowledge of the basic problems created by the radiation hazard. If not, he must rely on his monitoring team leader for technical advice in all decision making. b. The Monitoring Team Leader (one) will be responsible for obtaining and evaluating the radiation levels in the working area: (1) He will instruct his team members in the techniques of their specific duties and keep the group leader and team leaders supplied with pertinent radiological information through­ out the exercise; {2) he will determine average levels of radi­ ation for the working area and for aircraft to be decontaminated; (3) he will also calculate the "stay times" for various crewmembers to avoid exposure be­ yond the allowable dose limits established for the exercise; Chap 1 (4) he and his team members will act on orders from the group leader; and (5) he will also be responsible for main­ taining records of individual dosages for all members of the group. c. The Decontamination Team Leader (one) will be responsible for decontamination opera­ tions on the aircraft, equipment, and personnel. He will instruct his team members in the tech­ niques of their specific duties. He and his team will act on orders from the group leader and will be governed by information received from the monitoring team leader pertaining to "stay times" for his crewmembers. d. The Security Team Leader (one) will be responsible for enforcing the use of the CON­ TROL POINT as the ONLY entrance and exit between the "hot" area and the "clean" area. His team will be on constant alert to prevent interference with the operations and to help en­ force commands of the group and team leaders; he will also instruct his own team members in their specific duties. e. Assign Remaining Members of the group to one of the three teams. 3. EQUIPMENT. Review the equipment list in Appendix I and make assignments of specific equipment items for individual members to ob­ tain, for the group prior to the exercise. 4. CHOOSING AN AREA. Select a suitable area on the airport for decontamination work and consult with the airport manager to obtain his approval. a. Good drainage is the most important factor to consider. Without satisfactory drainage, the contaminated runoff water must be collected, pumped into containers, and transported to an approved burial site, which is a tedious and difficult method of disposal. If the ground is unusually porous , a large amount of runoff Par 1 ### Page 8 water will seep down to lower levels where danger of harmful levels of radioactivity at the surface will be negligible. If sewer-type drains, built into .a hard-surfaced area, will re­ move the contaminated water to a safe area (where persons will not be affected by the con­ centration of radioactive material), this method is ideal. If there is a collection or pool of con­ taminated water as a result of inefficient drain­ age, monitoring the pool will be necessary to determine if removal or a covering with several inches of earth is necessary. b. The immediate area where the aircraft is to be decontaminated need be only slightly larger than the wing span or overall length of the aircraft. The ID.EAL "washrack" area would be saucer-shaped, hard-surfaced, with a drain near the center, carrying all runoff water to a point some distance away, depositing the contamination three or more -feet below the surface. (If you have any questions or doubts about your drainage area, it is suggested that you discuss this matter with your local Civil Defense Director.) A large tarpaulin can be laid on sloping ground in lieu of a hard-sur­ faced washrack. The runoff water can be di­ rected from the lower edge of the tarpaulin into a drainage ditch or hole for burial purposes. c. Criteria for a good decontamination site. (1) Best possible drainage. (2) Hard surface with drain or very porous soil. (3) Close proximity to water supply. (4) Isolated 500' to 1,000' from other air­ port activity. (5) Sufficient space for all the working areas shown on the "Typical Area Sketch Map." (For practice purposes, the area might be lo­ cated at any usable portion of the airport; how­ ever, the airport manager may prefer to start developing a permanent location for decontami­ nation work and desire that the exercise be held at that preselected location.) 5. PLANNING AREA UTILIZATION. Draw a sketch map of the area selected showing the location of the washrack, hot and clean areas, etc. Using the sketch map on page 5 as a guide, prepare a sketch showing the general "layout" for your Par 4 AC 20-48 1966 particular exercise area and reproduce it so that all members of the group will have a copy and become familiar with the plan before the exer­ cise. The area plan should be oriented on the day of the exercise to accommodate the exist­ ing wind direction. The "clean" area should be upwind of the "hot" area so that any dust or contaminated water spray from the "hot" area will not be blown across the "clean" area. 6. SETIING UP A PROBLEM. Specific ground rules and limits must be established to perform the exercise both practically and effectively. Keep the practice problem simple. Use only one light aircraft. Assume the following conditions in your problem: a. Assume the aircraft escaped blast and thermal damage but was covered with fallout where it was parked. b. Assume the entire land area is contami­ nated; however, a few days after the fallout ceased, natural decay has reduced the level of radioactivity so that it is safe to begin recovery operations with limited "stay times." c. Assume a decontaminated "clean" path has been prepared for personnel and vehicles ex­ tending from the shelter to, and including, the assembly area. Also assume that the entire "clean" area is decontaminated. This will pro­ vide working room. In a real situation, the de­ contamination process might have to begin at the exit of the shelter before any personnel or equipment proceeded to the decontamination site. d. Assume a buffer zone is cleaned beyond the limits of the cleaned areas shown on your sketch map, making it safe to occupy all of the "clean" areas. For ALL exercises, use the fol­ lowing allowable limits: (T) Maximum limit of dosage for any in­ dividual shall not exceed 14 mr. during one exercise, or in any one day, if more than one exercise is attempted the same day. (Normally only one exercise is held in any one day.) As an extra safety measure, this 14 mr. limitation is only ½ of the allowable dose for training purposes, Office of Civil Defense (OCD), Tech­ nical Bulletin 11-1. In actual emergencies, much higher exposures are likely to be required. Chap 1 ### Page 9 AC 20-48 1966 (2) After completing decontamination of an aircraft, at no point on the aircraft will a reading of more than 0.5 mr/hr. be acceptable. (Lower readings can be expected as a result of a thorough scrubdown.) (3) Outer (protective) clothing should be decontaminated to a maximum permissible reading of 0.5 mr/hr. (4) Parts of the body and any clothing worn under the protective clothing should not exceed 0.3 mr/hr. Respiratory protective devices should be cleaned to a maximum reading of 0.3 mr/hr. Remove the canister, before washing the respirator, to avoid damage to the filter ele­ ment. (Do not let water enter the air intake end of the canister when washing, otherwise the full mask must be washed inside and out.) (5) The monitoring team leader should pre­ pare slips of paper on which the monitors will find figures representing four "assumed" levels of radiation - one for each of the four direc­ tions (North, South, East, and West) which they will face when taking area readings. The monitors will average these figures and enter the average for the quadrant on the monitor­ ing report form used during the exercise. For example, the "hot" area can be roughly divided into four quadrants. The monitors will proceed to the center of each quadrant and enter the average of all four "assumed" levels of radio­ activity in the appropriate place on the sketch map, thus simulating the taking of actual read­ ings. (CAUTION: Monitoring of aircraft and all personnel returning from the "hot" area to the "clean" area must be done by instrument. Only the background levels should be simulated or assumed. If used, radioactive uranium-ore sand will register on the instruments when monitoring a contaminated aircraft or person­ nel who have been contaminated. DO NOT **SIMULATE THE READINGS FOR EITHER THE AIRCRAFT OR PERSONNEL. 1).** 1 In Chapter 2, Phase II, Paragraph 24, you are di­ rected to multiply the actual aircraft readings by 200. This is an exercise procedure which is necessary in order to have a mathematical figure which is large enough so that you can subtract the assumed back­ ground radiation figure to obtain the aircraft level. It is suggested that the "hot" area background radiation level readings for the various quadrants be preset for the exercise somewhere in a 10-30 mr/hr. range. Chap 1 Page 3 7. SETIING EXER~ISE TIME AND DATE. Coordinate the selected exercise time and date with the airport manager, control tower, fire chief, and others as necessary.­ a. PRE-EXERCISE TRAINING. The monitoring team leader, security team leader, and decontamina­ tion team leader should instruct their respec­ tive team members in their duties, and in the methods, techniques, and safety measures to be observed. Team leaders should meet with their team members (crews) before the exer­ cise in a pre-exercise training session. a. The Monitoring Team will be taught to read instruments, and the use of forms for re­ cording their readings, and they should be given practice in wearing and adjusting pro­ tective clothing. The monitoring team leader should underscore all passages in this guide which apply to the monitors' specific duties and review this material with his crew. b. The Decontamination Team leader will instruct his team in the techniques to be used, as described in this guide, the precautions to be taken to control the spread of contamina­ tion, and the proper use of protective clothing. He should underscore specific passages in the manual related to his team's duties and review the items with his crew. c. The Security Team personnel must have a thorough understanding of the area sketch map and be aware of the seriousness of their responsibility for keeping all personnel from wandering aimlessly about the area or from using any crossing points other than the CON­ TROL POINT in traversing between the "hot" and "clean" areas. It should be stressed that security personnel may be of assistance to all participants by observing their movements and calling attention to actions which might either endanger the participants or create problems of cross-contamination. d. Members of ALL teams are to be taught radiological safety procedures. External radia­ tion originates from a radioactive source out­ side the body. For example, gamma radiation from a piece of radioactive material outside the body is external radiation, since radiation pass- Par 6 ### Page 10 es from the material through the body. On the other hand, alpha particles do not penetrate the skin and, therefore, are not an external hazard. The danger from alpha particles occurs when they are ingested by breathing, eating, drinking, or if they enter through an open wound. External radiation can come from radio­ active fallout or other radioactive materials. Protection against external radiation consists of one or a combination of three factors ­ TIME, DISTANCE, and SHIELDING. (a) Time as a factor is easily understood. The dose received. equals rate multiplied by time. Therefore, it is important that the time spent in a radiation area be kept to the mini­ mum necessary to do the job. If the rate of radiation is 50 mr/hr., an exposure for one hour would give a person a dose of 50 mr. An exposure for ½ hour would give only a 25 mr. dose. (b} Distance is often the best protection available. For example the radiation received 10 feet from a radioactive point source would be approximately 1/100th of the radiation received at a distance of one foot. This is one reason for recommending the use of a long-handled AC 20-48 1966 brush during scrubdown, so that the operator can stand as far as possible from the source of radioactivity. (c} Shielding material must be dense to be effective for most external radiation. Con­ crete and heavy metals are very effective shields. If it is possible for the participant to carry on his work in a position where concrete, iron, steel, etc., are between his body and the source of radiation, this should be practiced. However, it may not be possible for the parti­ cipant to remain completely shielded and also accomplish his objective. During rest periods, crewmembers should take advantage of the shielding afforded by a vehicle, such as a water­ tank truck, as well as the protection of distance. Normally, the most readily available protection is a combination of time and distance. Personnel should stand as far from the source of radiation as possible and remain in the area the shortest time possible. All decontamination and monitor­ ing personnel must enter and leave the con­ taminated area through a single CONTROL POINT in order to control the monitoring and to reduce cross-contamination. This point must be stressed. Par 8 Chap 1 ### Page 11 AC 20-48 Page 5 (and 6) - '<;6 TYPICAL AREA SKETCH MAP / I ~ HOT AREA : CLEAN AREA ,I... PARK "CLEAN'' I Ajc HERE ·················, ....... DRAIN ~ PARKED NC FOR EXERCISE ® I @ I DECON EQUIPMENT RACK • UP-WIND OF AIRCRAFT ............•.... ,I MONITOR TEAMI STATIONCo,~'.>-1ro ~A DECON ~ 011\tl" TEAM **STATION I .....** SECURITYI\ATOM I/MARKER ,.I SIGNS I WIND .......___ ASSEMBLY AREA ### Page 12 AC 20-48 Page 7 1966 Chapter II. HOW TO CONDUCT THE EXERCISE Phase I 9. ASSEMBLY. All personnel and equipment should move into the "clean" assembly area via the previously decontaminated path leading from the shelter. Be certain that the group understands the problem and all assumed con­ ditions of the exercise. Emphasize the locations of the stations, washrack, and outer limits of the area, etc. (It is advisable to place tem­ porary stakes at the four corners of the area, and at station locations. If possible, the area should be roped-off to indicate boundaries.) 10. SECURITY PERSONNEL. Post security person­ nel around the assembly area to keep people inside the "clean" area. 11. EQUIPMENT. Check the equipment for ade­ quacy and completeness. 12. CLOTHING. Issue personal protective cloth­ ing and equipment to monitors and decontami­ nation team members; issue arm bands and dosimeters (if available) to all personnel. 13. FINAL BRIEFING. The entire group should be briefed by the group leader to explain, in se­ quence, the order of procedure for the exercise. This is an oral "dry run" of the exercise to let everyone visualize the process. It will help reduce possible confusion and error. Do not actually use any equipment during the dry run. The final briefing may also be used to clear up a variety of last minute items. a. If the teams or any of their members have not practiced "dressing out" in their pro­ tective clothing, this practice should be part of the final briefing. b. If any last minute changes in the orienta­ tion of the area are required due to wind shift, this is the time to do so. c. Last minute individual assignments can be made or changed at this time . Chap 2 d. Questions from the group should be en­ couraged, to be certain that every team mem­ ber understands his assignment. 14. DRESS OUT. When decontaminating aircraft, team members must wear protective clothing, which they should now put on under super­ vision of their team leader. The object is to keep the contaminated water from soaking through to, or touching, the skin. Gamma rays cannot be prevented from penetrating the clothing ( one reason for limiting "stay" or "exposure" times), but beta particles, which will cause severe burns, can be kept from reaching the skin by wearing the proper clothing. The inhalation of dust or contami­ nated water spray can be prevented by wearing a face mask. Water-repellent clothing permits washing off the particles which emit gamma rays, thus reducing the exposure of the person wearing the protective clothing. When "dress­ ing out," observe these simple procedures: a. Make all joints of two-piece protective clothing overlap from top to bottom. b. Keep the head covering outside the jacket; the sleeves outside the glove cuff; and the trouser-leg bottom out.side the boot top, so that water will run off rather than run down inside the clothing at the neck, wrists, or ankles. c. The clothing should be closely taped at the juncture of the sleeves and rubber gloves, at the edges of the face mask, and at any points where water might splash or run inside. d. Cover all buttons, seams, side vents, or small holes in clothing with masking tape. e. Seal all locations with tape at points where dust or water spray could enter. f. Leave a one-inch fold-over tab on the ends of the tape. (This makes it easier to remove the tape with the bulky protective gloves, which are the final items of protective clothing to be removed.) Par 9 ### Page 13 Pqe 8 15. TAKE STATIONS. All three teams should now move from the assembly area to their respec­ tive team stations. At the same time, move all decontamination equipment to the team stations. Team stations are located in the "clean" area because: a. It provides team members with a pro­ tected area to which they can retreat when they are not working. (This gives them the added protection of the distance between the station and the source of radiation.) b. All personnel should be exposed to radia­ tion as little as possible and for the shortest possible period of time. c. Once the exercise has started, strict en­ forcement of NO SMOKING, EATING, or DRINKING rules must be observed in the working areas, as well as in the team stations. (The ban can be lifted when personnel have been cleared AFTER their final monitoring.) 16. MONITOR "HOT" AREA. Two or more moni­ tors will now make a survey of the "hot" area and record their "average" readings on their copies of the sketch map, indicating where the readings were taken. Monitors will return to the CONTROL POINT and give the maps to their team leaders. a. The method for "area monitoring" differs somewhat from "equipment" and "personnel" monitoring. In area monitoring, readings are taken at a level 3 feet from the ground. (1) The instrument or-if so equipped­ the probe is held parellel to the ground with the shield open. (2) The monitor proceeds to the center of a particular quadrant and takes four readings, facing the North, South, East, and West to take the separate readings, after which he av­ erages them and records the average figure on the sketch map for that particular quadrant reading. (3) Although monitoring is done as quickly as possible to avoid excessive exposure; in a real situation, much depends on the ACCU­ RACY of these readings. Therefore, the monitors should take sufficient time to assure a steady needle reading or, if the needle refuses to stop Par 15 AC 20-48 1966 oscillating, decide on the average needle read­ ing and use that figure. (4) Monitors should visually spot the ap­ proximate centers of the quadrants before leaving the CONTROL POINT so that they can walk unerringly to their check point. Aimless wandering in a radiation field should be avoid­ ed. This part of the exercise should emphasize practice in monitoring an area with minimum exposure of personnel. b. After the "hot" area is monitored, the monitors return to the CONTROL POINT rather than to their respective stations. Be­ cause no decontamination equipment has yet been moved into the "hot" area, there is no way to wash down the monitors in the event their clothing has become heavily contami­ nated. If the "hot" area radiation level during an actual situation were high enough to neces­ sitate the return of these men to their stations, all procedures would be delayed until a unit of decontamination equipment had been moved into the "hot" area so that these monitors could be rinsed off. In this type of situation, it is ideal to have a portable shower unit. However, the exercise can be accomplished without these facilities. If you are equipped to include personnel showering as part of your exercise, the following information will be helpful: (1) A special area should be provided for personnel to remove contaminated clothing be­ fore entering the showers. ( Ordinary metal trash cans with covers may be provided as clothing receptacles. Personnel without protective cloth­ ing should not be permitted within this con­ taminated area). The showers should be located in a buffer or transit zone between the con­ taminated and uncontaminated areas. (2) N onnally, the same procedures that remove ordinary dirt from the body will also remove radioactive contamination. (3) Personnel should use an abundance of soap and water, thoroughly scrubbing the body, hair, hands, and fingernails. (4) After the shower, personnel should be monitored and any residual contamination re­ moved by spot-cleaning or further showering. (If a person has an injury or a wound, he should Chap 2 ### Page 14 AC2~8 1966 make this fact known to medical personnel so that special medical precautions may be taken to prevent contamination of the wound_ during re­ covery operations.) (5) Following the shower procedure, a "clean" area for dressing purposes should be specified. At no time should contaminated per­ sonnel or equipment be permitted in this area. 17. CALCULATE AREA RADIATION. The monitor­ ing team leader calculates the average level-of­ radiation for the entire "hot" area and dispatches monitors to install the atom-marker signs. a. Calculate the Area Average by adding all the quadrant readings and dividing by the num­ ber of readings used. The result will give the average area level figure. This will be used as the background level for the "hot" area, in­ cluding the washrack. b. The Monitor Team Leader now calculates the "stay times" for the security team personnel and gives the stay-time figure to the security team leader. (Plan on posting security guards 3 feet inside the atom-marker line on the "clean" side.) The monitoring team leader must con­ stantly be thinking of exposure time for all personnel. If in doubt, he should call for a read­ ing of the dosimeters on the individuals in ques­ tion and, if necessary, take time to recheck his "stay-time" figures. This is one reason for not rushing through the procedure. THE SAFETY OF ALL PERSONNEL DEPENDS TO A LARGE EXTENT ON THE CARE AND AC­ CURACY WITH WHICH BOTH EXPOSURE AND DOSAGE ARE KEPT UNDER CON­ TROL. c. "Stay times" are calculated to determine the period that a person may remain in a given area at a given level-of-radiation without ex­ ceeding his allowable dose limit. The problem sets the close limit at 14 mr. per person. To calculate the area "stay time" for the monitor­ ing and security teams, divide the figure 14 by the area-average level. This will give the num­ ber of hours or fraction of an hour for "stay time." Usually, the area level figure will be greater than the dose limit figure 14. For ex­ ample, if the ~verage area level is 56 mr/ hr. and dose limit is 14 mr., then 14 divided by 56 gives 0.25 hours. Thus the stay time would be Chap 2 Page 9 ¼ hour or 15 minutes. By using the same figure and checking with dosimeter readings, it can be determined if those monitors who were used in monitoring the."hot" area in item 16 have consumed their allowable "stay time." If they have, other members of the monitoring team will be used to conduct further monitoring op­ erations required in the steps to follow. 1B. POST SECURITY. The security team leader now posts his personnel at the CONTROL POINT and along the atom-marker line. (It would be possible to operate a decontamination area without security personnel but this would require the gamble of self-discipline on the part of all concerned.) Security personnel should stay within the bounds of the "clean" area at all times and control traffic through the CON­ TROL POINT making sure that no person or equipment is permitted to leave the "hot" area without first being monitored. The posting of security personnel is done with the minimum number of guards possible. The reason for this is to conserve manpower and reduce the total exposure of security personnel. One or two security guards should be sufficient to handle the CONTROL POINT, and two or three se­ curity guards can be assigned to patrol the remainder of the atom-marker line. The func­ tions of the security team leader are to provide maximum safety at all times by: a. Using SECURITY PERSONNEL to pre­ vent cross-contamination b. Using an ALERT SECURITY TEAM to provide an additional check on all safety meas­ ures being used by monitors and decontamina­ tion team members; and c. Using CAUTION in exposing oneself or others to unnecessary dosage. 19. MONITORS - CONTROL POINT. The moni­ tors are sent to the CONTROL POINT to monitor all personnel and equipment returning to the "clean" area from the "hot" area. (When not needed at the CONTROL POINT, the monitoring team leader and his crew may with­ draw to the team station to reduce their ex­ posure.) a. The monitors must know the techniques of monitoring both personnel and equipment: Par 16 ### Page 15 (1) The monitors, with the backup of the security guard, must insist on monitoring any­ thing or anybody moving through the CON­ TROL POINT from the "hot" area to the "clean" area. (2) The monitoring team leader, not the monitors, are to make the decisions in the re­ quirement for the decontamination of equipment and personnel before they are cleared into the "clean" area. (3) The monitors call out their readings to their team leader when monitoring at the CONTROL POINT. (4) Other readings, such as the area read­ ings and those taken on the aircraft, will be entered on the proper form and brought to the team leader. (5) When taking readings on personnel, use a type CD V-700 meter; open the beta shield on the probe. (6) DO NOT TOUCH THE PERSON BE­ **ING MONITORED** (7) Direct him to raise his arms to a hori­ zontal position and stand with feet apart so that all parts of his clothing and body can be monitored. (8) Hold the probe approximately one inch from the clothing or body being monitored. (9) DO NOT ALLOW THE PROBE TO TOUCH THE BODY OR CLOTHING. Monitor the face, neck, scalp, palms, and backs of hands, wrists, ..sleeves, chest, back, trouser seat, trouser leg, ankles, and shoes. (10) Detect the radiation by means of the headset. (You will not be able to observe the meter needle while you are watching the probe position in an effort to keep it from touching the body or clothing.) (11) When the "clicks" in the headset signal the presence of radioactive material, hold the probe at that point and observe the reading from the instrument dial before pro­ ceeding. b. Equipment monitoring is essentially the same as personnel monitoring: (1) Localized or heavy contamination, in­ dicated by high readings, will be noted by the monitoring team leader. Par 19 AC 20-48 1966 (2) The monitoring team leader will ad­ vise the decontamination team leader when further washdown is required, and will specify the particular parts of the equipment requiring additional attention. This will save water and cut down the exposure time of the personnel performing the work. 20. CONTAMINATION OF AIRCRAFT. Two or more decontamination team members should now proceed to the parked aircraft, apply the uranium-ore sand, and return to their station. Contamination of the aircraft is accomplished by sprinkling the contaminated sand on the aircraft surface where fallout would most naturally be deposited on a parked aircraft. Since fallout settles by gravity, most of it may be found on the topside of the horizontal sur­ faces. Some fallout may be windblown into areas where it becomes trapped by an oily or greasy film or in the heavy carbon area on the backside of the exhaust stacks. It will also collect in surface irregularities such as screw­ heads, latches, edges of access plates, joints, seams, hinges, rough areas such as abrasive walkways, and around the window and door frames. Painted and unpainted aluminum sur­ faces have similar affinity for contaminants. If the aircraft is clean to begin with, an oily rag may be used to prepare special spots on the surfaces where you may desire to make the sand adhere. Do not waste the sand by trying to hide it in out-of-the-way places. There are plenty of areas in the open which will give sufficient practice in decontamination for the first few exercises: a. It will take 10 pounds of uranium-ore sand for one exercise on one aircraft. Because this sand has such a low level of radioactivity, much more sand (by volume) is used in an exercise than nonnally would be deposited by fallout to give off an equal radiation intensity. b. Dampen the sand before handling. In the dry form, it will stir up clouds of dust which might be inhaled by unprotected personnel. It might also blow off the aircraft while taxiing to the washrack. For this reason, and also to pre­ vent the sand from shaking off if it is necessary to taxi over rough ground, you may prefer to move the aircraft onto the washrack (see para- Chap 2 ### Page 16 1966 AC 20--48 graph 21) before applying the sand to the air­ craft. c. It is recommended that the 10 pounds of sand be divided into several portions and applied to 8 or 10 different locations on the aircraft. Apply approximately one pound of sand over a 6- or 8-inch square area-about ¼ of an inch deep. This should give readings between 0.15 and 0.3 mr/hr. d. If, when monitored at the CONTROL POINT, these team members are contaminated above the acceptable limits (0.5 mr/hr.) for outer protective clothing, they cannot be cleared back to their station in the "clean" area. The men will either have to remain there until the decontamination equipment is brought for the aircraft scrubdown or a special unit of equip­ ment will have to be brought in. It is very possible that only their gloves will be contam­ inated and a bucket of water will be sufficient to wash off the contamination. 21. MOVE AIRCRAFT INTO POSITION. The pilot taxis the aircraft onto the washrack (facing the wind) and stops the engine. 22. POSITION MONITOR. A monitor takes po­ sition about 50 feet from the exit door of the aircraft, prepared to monitor the pilot. 23. MONITOR PILOT. The pilot leaves the air­ craft as soon as it is parked on the rack and approaches the monitor for personal monitoring. Readings are to be reported to the monitoring team leader who would, in a real situation, de­ termine if the pilot required a change of cloth­ ing, shower, etc. If the pilot is contaminated, he should be processed in the same manner as the decontamination team members who con­ taminated the aircraft. (See paragraph 20d). 24. MONITOR AIRCRAFT. Monitors are now dis­ patched to take readings on the aircraft and return to their station via the CONTROL POINT. A report form should be designed for the monitors to use, similar to the sample Aircraft Monitoring Report form on this page. A list of suggested entries for monitoring are shown in the sample. You may desire to change or to add other entries due to the model of air­ craft being used. Chap 2 Page 11 a. The meters should show about 0.15 to 0.3 mr/hr. Multiply this by 200 (for exercise pur­ poses) and subtract the background figure. Enter the difference on the Aircraft Monitoring Report form. Example: Meter reading of 0.2 mr/hr, X 200 = 40, subtract the assumed back­ ground level of 20 and enter 20 mr/hr. on the Aircraft Monitoring Report form. b. When monitoring the aircraft, keep the probe a constant distance (l to 2 inches) from the surface. By maintaining this same distance when remonitoring the aircraft, a valid com­ parison of first and second readings may be made for any area of the aircraft. Never allow the probe to touch a contaminated surface as some of the contamination could adhere to the probe. Thereafter, this contamination would result in false readings. If the instrument does become contaminated, it should be wiped off and monitored with another instrument before being used again. **AIRCRAFT MONITORING REPORT** **AIRCRAFT IDENTIFICATION** LOCATION ON A/C 1st Reaclil! 2nd Reading .1-'!L Readi,g **PROPELLER** **TOP ENGINE COWLING** **TOP RIGHT WING** **TOP LEFT WING** **TOP FUSELAGE** LANDING GEAR RIGHT LANDING GEAR LEFT r:::,.. TAIL SURFACES RIGHT (pr k:) - TAIL SURFACES LEFT "~{./12 ~­ DOORS ~i,J,..o)r> WINDOWS - t!.l)~ WIND SHIELD ~ DATE TIME MONITOR Par 20 ### Page 17 c. After completing their work, the monitors return to their station via the CONTROL POINT. If personal monitoring at the CONTROL POINT indicates their protective clothing has a reading of less than 0.5 mr/hr., they can proceed to their station. Otherwise, they will have to wait at the CONTROL POINT to be washed down before they return to their station. (See paragraph 16.) 25. CALCULATE THE STAY TIME. The Monitoring Team Leader now calculates the stay times for the decontamination crew members and gives a copy of the Aircraft Monitoring 'Report to the decontamination team leader. In order to figure decontamination crew member "stay time," divide the average of the aircraft read­ ings (multiplied by 200) plus background level into 14. Example: Instrument XI scale reading of 0.2 m.r/hr. X 200 = 40.0 mr/hr. plus back­ ground of 30.0 mr/hr. gives 70.0 mr/hr, which divided into 14 gives 0.2 hours or 12 minutes stay time. Phase Ill 26, FIRST SCRUBDOWN. The decontamination team now moves its equipment into the "hot" area to a position on the upwind side of the washrack and proceeds with its decontamination work, keeping in mind the following principles and procedures: a. General Principles (1) Radioactive material cannot be destroy­ ed; most decontamination processes are de­ signed for removal of contaminants from a surface or the removal of the surface itself. Radioactive material, at best, is merely moved from one place to another. (2) It is advisable to learn the basic methods and techniques of exterior decontamination work first and attempt interior decontamination later. (3) Clean water is a precious commodity in an emergency; therefore, learn to conserve it. (4) Remove contamination with a minimum amount of water and with a minimum exposure of personnel to the radiation. (This includes spraying or splashing of contaminated water on personnel.) Par :l4 .AC 20-48 1966 (5) When removing the aircraft contami­ nant, use gr~at care to control the runoff water (which contains a concentration of radioactive material) from the aircraft. The_ need for care in this cannot be overemphasized. (6) When washing down aircraft remove the pressure hose nozzle, using a flow-on appli­ cation of the water, since direct pressure will damage light aircraft coverings. (This also re­ duces the amount of water splashed and sprayed around the area, and will help to reduce the spread of the contaminated material as it is loosened and washed from the surfaces of the aircraft.) (7} Cover any accumulated contaminant with earth to provide a greater protective factor. This lessens danger to personnel in the vicinity. Burning or other common means of destruction are futile with radioactive materials. Burial be­ neath the earth's surface provides the best known method of disposing of such material. b. External Decontamination (1) Position the decontamination equipment upwind from the aircraft to reduce the amount of spray or splashing of contaminated water on the equipment. On windy days, spray from a careless application could be wind-blown several hundred feet. (2) The monitors' report will most likely show a concentration of radioactivity in greasy or oily locations which will necessitate scrubbing with brushes and the use of rinse water. (3) Use long-handled brushes for scrubbing operations to permit decontamination personnel to stand as far as possible from the aircraft, givini them the added protection which distance provides. (4} Mix soap or detergent into one or more buckets of water and carefully dip the brushes into this soapy water and apply to the aircraft. (5) Scrub the surface and make certain that the oil or greasy film is loosened and prepared for rinsing off by hose. On smooth clean sur­ faces, fallout is easily removed by a flow-on application of water. (6} Apply water to the surface of the air­ craft, working from top to bottom and front to rear (assuming the aircraft is parked facing the wind.) Decontamination crew members Chap 2 ### Page 18 AC 20-48 1966 should stand windward of all scrubbing and hosing operations. (7} Play the water directly on the contam­ inated surface so that contamination is removed with a minimum of wasted water and a mini­ mwn of splash. (8} Apply hose water at an angle of ap­ proximately 30-40 degrees, pointing down-wind. A sharp angle, such as 80-90 degrees, will splash and spray contaminated water back onto areas previously cleaned. c. Interior Decontamination (1) Interior decontamination is more diffi­ cult to accomplish than exterior decontamina­ tion. Decontamination of the interior of aircraft can be started by using a vacuum cleaner to remove loose radioactive debris and dust, prin­ cipally in corners and in locations that are dif­ ficult to clean. The monitors can poinpoint the locations of radioactive dust concentration. Great care must be taken in handling the vacuum cleaner after usage. Contents of the disposal bag containing the radioactive material should be disposed of as solid waste material, preferably by burial. Although special filters might not be required for the vacuum cleaner as used in the exercise, such filters would probably be essential for actual emergency conditions. (2) After the interior of the aircraft has been vacuumed, part of it, depending upon the construction materials, may be scrubbed with a solvent, using soft fiber brushes or wiping rags. A detergent and water wipedown may be used in the cabins of the aircraft. The direct application of a water hose in aircraft interiors is undesirl:lble for obvious reasons. 27. CLEAN PERSONNEL AND WASHRACK. Before leaving the washrack, the decontamination team should hose down or rinse off each other and then hose or wash the runoff water (which usually collects under the aircraft) down the drain. It may be necessary to wait a few minutes until the runoff water has stopped ( or nearly stopped) dripping from the aircraft. Personnel will then return to their station via the CON­ TROL POINT where a monitoring check will determine if they require further rinsing off before being permitted to proceed to the clean area. Chap 2 Page 13 28. REMONITOR AIRCRAFT. Monitors will now remonitor the aircraft, entering their readings in Column 2 of the report form, and then return to their station and give the readings to their team leader. The instrument readings taken by monitors are to be multiplied by 200, as before, with the washrack background figure sub­ tracted. (See paragraph 24.) **29. DETERMINE IF SECOND SCRUBDOWN NEEDED.** The team leader determines if the aircraft is now above or below the established limits of permissible radiation. The team leader advises the gToup leader of the results, and the group leader will determine if a second scrubdown is necessary. (Do not forget that the aircraft read­ ings have been multiplied by 200. Thus, they must be corrected before comparing the final decontaminated aircraft reading with the .05 mr. allowable limit. This limit is set only for purposes of the drill. Under emergency condi­ tions, much higher limits may be appropriate as discussed in the FAA Publication "Radio-­ logical Protection and Decontamination of Civil Aircraft." ) 30. SECOND SCRUBDOWN. If required a second scrubdown will be limited to those areas requir­ ing special attention. The monitoring team leader will advise the decontamination team leader of the location of these areas of remaining radiation activity. Care will be taken not to spread contamination (by water smear) to other parts of the aircraft previously cleaned. Clean the washrack and personnel as previously de­ scribed and withdraw to the assigned stations. 31. RECHECK BY MONITORS. Same as paragraph 28 except that the readings will be entered in Column 3. The monitoring team leader reports the results to the group leader. 32. REMOVAL OF AIRCRAFT. When the aircraft is affirmed as clean by the group leader, the pilot will taxi the aircraft from the washrack to the "clean" area and park it. Phase IV 33. MONITOR EACH VEHICLE AND UNIT OF EQUIP­ MENT. Monitor each vehicle and unit of equip­ ment used in the decontamination work. The monitoring team leader then advises the de- Par 26 ### Page 19 contamination team leader of the units of equip­ ment that require a washdown: a. Decontaminate the equipment as required. b. Remonitor the equipment. c. When all equipment readings are reduced to a level within allowable limits, decontamination and monitoring personnel will then hose and rinse off each other and proceed to the CON­ TROL POINT with their equipment. 34. MONITOR PERSONNEL. The decontamination and monitoring personnel are monitored at the CONTROL POINT, while still in protective clothing to determine if further cleaning is neces­ sary before removing the protective clothing. 35. REMOVAL OF PROTECTIVE CLOTHING. Pro­ tective clothing can now be removed by all personnel. Appropriate procedures for the re­ moval of protective clothing may depend upon the clothing used and the nature of the hazard. It is good practice to remove first those items most likely to be cont:aminated. Assist:ance by other persons can be very helpful. a. It is important to keep from touching any protective clothing with bare hands, or allowing the protective clothing to rub against exposed skin or underclothing. The inside of each piece of protective clothing should be free of contam­ ination. b. Carefully remove head coverings with as little jarring as possible, as contamination could fall or drip onto the head, hair, neck, etc. c. Remove other pieces of clothing with equal care, working generally from the top and pro­ ceeding downward. d. Place all removed protective clothing in a pile. e. REMOVE GLOVES LAST. 36. FINAL MONITORING CHECK. Make a final monitoring check of the personal clothing worn under the protective clothing. and a thorough check of the body, head, neck, hands, feet, etc. If readings are above allowable limits, the mon­ itoring team leader will determine the extent of further decontamination necessary such as a change of clothing, showering, etc. 37. READ INDIVIDUAL DOSIMETERS. Individual do­ simeter readings should now be t:aken from each member of the group. Par 23 AC 20-48 1966 a. The readings of the dosage received during the exercise will be recorded by the individual on his PERSONAL RECORD OF RADIATION DOSAGES RECEIVED form. (See sample form below.) This form should remain in the pos­ session of the individual. b. Organized groups should keep a permanent record copy of the individual doses for everyone in the organization. Because of the extremely low-level activity of the uranium-ore sand being used and the short periods of exposure, some dosimeters may not give satisfactory indication of dosage received. In this case, the monitoring leader may prepare a calculated dosage figure which the individual will enter on his personal dosage record form. c. This calculated figure, if used, can be based on the length of time the individual remained in the "hot" area and the average rate of radia­ tion to which he was exposed. This will not eliminate the requirement for monitoring all personnel when leaving the "hot" area. **PERSONAL RECORD OF** RADIATION DOSAGES RECEIVED NAMEJ.~ j){Je A0DRE! 17 O'aA.Jx: ~ ~ Date radiation recei"Ved RADIATION DOSAGE Received this date Accumulated to date RoentgensRoentgens 1/10/61. .001 .001 7/fi/6l .003 .00,f, T/f8/6Z .001 .oos ,,..... (!J)v,/4) - ~1/i'v:', "((( >D) .... ~ -/;:.~ 'vcf.cl'-' - Chap 2 ### Page 20 AC 20--48 Page 15 (and 16) 1966 Chapter Ill. CRITIQUE OF THE· EXERCISE 38. CRITIQUE SESSION. Assemble all personnel and conduct the "critique" session immediately after the exercise while all events and actions are still fresh in the minds of the participants. a. The group leader should discuss his written comments and notations made during the plan­ ning and execution of the exercise. b. After discussing his comments and notes for each operation, the group leader should permit ample time for suggestions, observations, and criticisms from team members. c. Particular attention should be given to: (1) The effectiveness of the protective clothing used. (2) The adequacy of the water supply, amount used per aircraft, and methods to con­ serve water. (3) Was the drainage satisfactory? If not, how can it be improved? (4) What techniques used were well exe­ cuted? What techniques were used that were not satisfactory? Reasons? (5) Were there any problems encountered in trying to prevent cross-contamination? Solution? (6) Were any difficulties encountered in the monitoring and decontamination of personnel? Solutions? (7) Did the security team have any situa­ tion that could not be controlled? (8) How could facilities for decontamination of personnel be improved, such as providing a field shower, etc.? (9) Was the marking of the danger area ("hot" area) satisfactory? (10) Were any soaps, detergents, or solvents used that were unsatisfactory? What appeared to work best? (11) Were there any problems involving communication among group leaders, team leaders, and team members? (12) Were all personnel impressed with the primary importance of accomplishing the de­ contamination work in a manner to provide the maximum protection for everyone concerned? d. Summarize and indicate how the next ex­ ercise can improve on this one. e. Schedule the next exercise. Chap 3 Par 38 ### Page 21 AC 20--48 Page 17 1966 Appendix I. EQUIPMENT Equipment List Quantity Radiation detection meters . . . . . . . . . . . . . . . . . . . . . . . 1 to 6 Personal dosimeters . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 per person Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 gals. (Minimum) Scrub brushes (long handles) . . . . . . . . . . . . . . . . . . . . 1 to 6 Detergent, solvent, or soap . . . . . . . . . . . . . . . . . . . . . . 2 to 4 lbs. Protective clothing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 complete outfit for each member of monitoring and decontamina­ tion teams. Atom-marker signs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 to 12 Arm bands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 per person Vacuum cleaner 1 (required only for advanced classes) Aircraft … 1 Contaminant (simulating fallout) . . . . . . . . . . . . . . . . . 10 lbs. Water pails . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 to 4 1. RADIATION DETECTION METERS (GEIGER COUNTERS). For a practice exercise, the Civil Defense low-range model CD-V-700 (0-50 mr/ hr.) is recommended. The military equipment is model AN/PDR 27 or 27A. It is necessary to have a minimum of one Geiger counter. If pos­ sible, borrow several counters, so that more peo­ ple can be given the opportunity to learn how to use them. Arrangements should be made to bor­ row these instruments from one of the follow­ ing sources : a. Federal Aviation Agency station or tower. b. Department of Defense Installation (Army, Navy, Marines or Air Force) . c. Weather Bureau. d. Civil Defense Unit ( county or local). e. High School or College Science Department. 2. PERSONAL D051ME1i:RS. Low-range picket­ type dosimeters may be borrowed (from the same sources) for each person in the group. The Civil Defense model DC-V-138 is the equiv­ alent to military model No. IM-9. These dosime­ ters are preferable to the film-badge type only because they are self-reading. A dosimeter charger, Civil Defense model CV-V-750, is n'ecessary in order to reset the dosimeter hair­ line to zero or to bring the line onto the scale so that a starting and ending reading can be taken. 3. WATER. As far as possible, water used for decontamination purposes should be clean or free of contamination . If, at your airport, it is necessary to use water pumped from an open body supply, place the intake end of the hose 1 or 2 feet below the surface, but not on the bottom. Fallout which descends on open water will either sink to the bottom (heaviest par­ ticles) or float on the surface (lighter dust). If water is obtained from a tank or covered well, ### Page 22 P19e 18 it will probably be free of contamination. Local fire trucks equipped with tanks may be avail­ able, which would greatly simplify the water problem for this exercise. 4. SCRUB BRUSHES. Any fiber brush will be satisfactory, provided it has a long handle. Fairly soft bristles and a good size brush-head, 2½ or 3 inches by 8 or 10 inches, are preferable. 5. DETERGENTS, SOLVENTS, OR SOAPS. Ordinary soaps and detergents found in any grocery store are satisfactory. Where fallout has been em­ bedded in or adheres to an oily or greasy spot, the addition of soap to the water will greatly increase the efficiency of decontamination work. Although it is unlikely that heated water or a steam jet will be available, they are both very effective in removing grease and oil. 6. PROTECTIVE CLOTHING. This is the most im­ portant of all the equipment needed for your exercise. IF YOU CANNOT PROTECT YOUR PERSONNEL WITH WATERPROOF CLOTH­ ING, DO NOT ATTEMPT THE EXERCISE. However, it is neither difficult nor expensive to obtain the clothing required for adequate pro­ tection. The following items must be included: waterproof boots waterproof suit with hood (hip boots and a slicker type raincoat and a separate hood AC 20-48 1966 can be substituted) rubber gloves (waterproof fabric gloves can be substituted, but do not take chances on contamination soaking thr_ough to your skin) protective face mask Use 2-inch wide masking tape or waterproof ad­ hesive tape to seal clothing joints at ankles, wrists, waist, neck, and to cover zippers and close any other openings wllere moisture might possibly penetrate the protective clothing. 7. ATOM-MARKER SIGNS. The control of con­ tamination, which is a major problem, can be materially assisted by "fencing off" specific areas. Remember that contamination can be spread by tracking on shoes. Vehicles can also track contamination from one area to another. Valuable and much needed equipment" could be out of service for long periods if carelessly or unnecessarily driven into contaminated areas. a. The purpose of the atom-marker signs is to assist in controlling the spread of contamina­ tion. The signs should constitute sufficient warning to stop people from wandering into a "hot" area and returning to "clean" areas, which would result in cross-contamination. b. The signs may be handmade, but they should follow the approved Department of De­ fense design and dimensions as closely as possible. **DANGER ATOM** ### Page 23 AC 20-48 1966 The prescribed shape is a right-angle isosceles triangle with a base having a minimum length of 6 inches. The quantity of signs required will depend on the size of the area you wish to desig­ nate as a "hot" area. Signs should be placed 20 to 30 feet apart, to minimize the possibility of people walking into the area without observ­ ing at least one of the markers. Signs should be mounted on stakes, standards, or may be suspended from a rope barrier if used. The sur­ face on each marker should face away from the contaminated area. Signs are of little or no value if placed flat on the ground. 8. ARM BANDS. If you have a large group, it it advisable to provide identifying colored arm bands for each team. Otherwise it is almost im­ possible to identify people when they are "suited out" in full protective clothing. The team leaders should be given a distinctive identification such as a double arm band. Reflective tape can be used for night operations. 9. VACUUM CLEANER. This is not a required piece of equipment, at least for the first few exercises. However, when you are prepared to practice interior decontamination, the vacuum cleaner will be a very handy tool. A portable source of electrical power will be necessary if a vacuum cleaner is used. 10. AIRCRAFT. It is suggested that a small air­ craft be used for the exercise until the basic lessons have been learned. The contaminated sand will not damage the aircraft and all traces of radioactive material should be removed dur­ ing the exercise so there will be no danger to Page 19 personnel operating or working on the aircraft at a later date. Radiation will not interfere with the functioning of the engine or any other mechanical or electrical equipment aboard . 11. CONTAMINANT - RADIOACTIVE SAND. If pos­ sible, use a material which will simulate fall­ out in order to gain practical experience in the decontamination processes. Smearing mud on the aircraft has been tried, but without radio­ active material in the mud, DECON crews cannot be sure of complete removal. Therefore, obtain a contaminant which will provide a few milliroentgens of gamma and beta radiation . Such a material is available in the form of uranium-ore sandstone, which is finely ground and ready to use. It will take about 10 pounds of this to conduct one exercise on a light aircraft. Arrangements can be made with the Homestake­ Sapin Partners, P.O. Box 98, Grants, New Mexico, to organize one central distribution point in each state so that you -can place your order with that distributor. Your State Depart­ ment of Aeronautics or the Federal Aviation Agency General Aviation District Offices will be able to a.dvise where this distribution point is in your state. The cost of this radioactive sand, plus shipping charges (motor freight), will be approximately $1 to $1.50 for 10 pounds. 12. CERTIFICATE OF ACHIEVEMENT. Some organ­ izations may wish to give an award to their members in recognition of completion of pre­ paratory training and successful execution of this exercise. A suggested format for such a certificate is shown on page 20. ### Page 24 Page 20 AC 20-48 1966 Qtrrtificate of ~tbiebement AWARDED TO for--------------------­ at _________ _ Awarded this ______ _ day 0J____ J9 __ **ORGANIZATION AUTHORIZED SIGNATURE** ### Page 25 AC 2G-18 Page 21 1966 Appendix II. Alpha Particle-A particle emitted spontaneously from the nuclei of some radioactive elements. It is identical with a helium nucleus, having a mass of four units and an electric charge of two positive units. It travels only a few inches, even in air, but can be very harmful if ingested by breathing or taken into the blood stream through an open wound. Attenuation-The absorption or stopping of some of the radiation as it passes into or through solid materials. Beta Particle-A charged particle of very small mass emitted spontaneously from the nuclei of certain radioactive elements. Most, if not all, of the direct fission products emit (negative) beta particles. Physically, the beta particle is identical with an electron moving at high ve­ locity. The beta particle is the cause of beta burns to the skin, which may be very serious. Buffer Zone-An area that has been decont.ami­ nated immediately beyond and in addition to the intended working area. Clean Area-One in which decontaminating measures have been taken to reduce the amount of residual radioactivity. Contamination-Deposit of radioactive material on the surface of structures, areas, objects, or personnel following a nuclear (or atomic) explo­ sion. This material generally consists of fallout in which fission products and other weapon debris become incorporated with particles of dirt, etc. Cont.amination can also arise from the radio­ activity induced in certain substances by the action of neutrons from a nuclear explosion. Cross--contamination-The contamination of a pre­ viously "clean" area by radioactive material which is windblown, or tracked on shoes or vehicle tires, etc. GLOSSARY Decay-Sometimes referred to as "natural de­ cay," is the decrease of any radioactive material with the passage of time. Decontamination-The reduction or removal of contaminating radioactive material from a structure, area, object, or person. Decontamina­ tion may he accomplished by: (1) treating the surface so as to remove or decrease the contamination; (2) letting the material stand so that the radioactivity is decreased as a result of natural decay; (3) covering the contamination to attenu­ ate the radiation emitted . Radioactive material removed must be disposed of by burial on land or at sea, or by other suitable methods . Dosage (dose)--A total or accumulated quantity of ionizing (or nuclear) radiation. A dosage can be measured by reading a pocket dosimeter or it can be calculated by multipl~ing the hours of exposure times the rate of radiation, which is expressed in terms of roentgens or milliroent­ gens per hour. Dose Rate--As a general rule, the amount of ionizing (or nuclear) radiation to which an in­ diviqual would be exposed or which he would receive per unit of time. It is usually expressed as roentgens or milliroentgens per hour. The dose rate is commonly used to indicate the level of radioactivity in a contaminated area. Dosimeter-An instrument for measuring and registering total accumulated exposure to ioniz­ ing radiation (pronounced- dosimeter) . Gamma Rays (or Radiations)-Electromagnetic ra­ diations of high energy originating in atomic nuclei and accompanying many nuclear reac­ tions, e.g., fission, radioactivity, and neutron capture. Physically, gamma rays are identical ### Page 26 with x-rays of high energy, the only essential difference being that the X-rays do not originate from the atomic nuclei, but are produced in other ways. Gamma rays probably constitute the greatest threat in radioactivity and are the main reason for decontaminating-to remove the source of this type of radiation. Milliroentgen (mr)-A one-thousandth part of a roentgen. Monitoring-Procedure of locating and measuring radioactive contamination by means of survey instruments which can detect and measure (as dose rates) ionizing radiations. (The individual performing the operation is known as a monitor.) Radiation Levels-Measure of ionizing radiation at specified periods, usually read from survey meters as-mr/hr. or r/hr. Radioactivity-The spontaneous emission of ra­ diation, generally alpha or beta particles, often accompanied by gamma rays, from the nuclei of an unstable isotope. As a result of this emis­ sion, the radioactive isotope is converted (or decays) into the isotope of a different (daugh­ ter) element which may or may not also be radioactive. Ultimately, as a result of one or AC 20---18 1966 more stages of radioactive decay, a stable non­ radioactive end product is formed. Roentgen-A unit of exposure dose of ganuna (or X-) radiation. Survey meters and dosimeters show readings either in roentgen units or milli­ roentgen units. Stay Time-The period of time personnel can work or stay in an area at the existing dose rate of radiation without exceeding the prescribed maximum dose. Shielding-Any material or obstruction which absorbs (attenuates) radiation and thus tends to protect personnel or materials from the effects of a nuclear (or atomic) explosion. A moderately thick layer of any opaque material will provide satisfactory shielding from heat radiation, but a considerable thickness of ma­ terial of high density may be needed for nuclear radiation shielding. Survey Meter-A portable instrument, such as a Geiger Counter or ionizing chamber, used to detect and measure nuclear radiation. These measurements are in terms of the rate of radiation, either roentgens per hour or m.illi­ roentgens per hour. * U.S. Government. Printing Offic e : 19 9 1 · 517-000 / 46019 --- From OpenAirDocs.org, an independent open copy of FAA data. Only the Federal Register edition on govinfo.gov is the official legal text of an AD.