AC 20-48
PRACTICE GUIDE FOR
DECONTAMINATING AIRCRAFT
FEDERAL AVIATION AGENCY Flight Standards Service Washington, O.C. 20553
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
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
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.
AC 20-48 Page i 1966
TABLE OF CONTENTS Chapter I. HOW TO PLAN AND PREPARE AN EXERCISE Paragraph Page
1. Starting point1
2. Minimum organization1
3. Equipment1
4. Choosing an area1
5. Planning area utilization2
6. Setting up a problem2
7. Setting exercise time and date3
8. Pre-exercise training3
Chapter II. HOW TO CONDUCT THE EXERCISE
PHASE I
9. Assembly7
10. Security personnel7
11. Equipment7
12. Clothing7
13. Final briefing7
14. Dress out7
15. Take stations8
16. Monitor "hot" area8
17. Calculate area radiation9
18. Post security9
19. Monitors - control point9
20. Contamination of aircraft10
PHASE II
21. Move aircraft into position11
22. Position monitor11
23. Monitor pilot11
24. Monitor aircraft11
25. Calculate the stay time12
PHASE Ill
26. Fir st scrubdown12
27. Clean personnel and washrack13
28. Remonitor aircraft13
29. Determine if second scrubd own needed13
30. Second scrubd own13
31. Recheck by monitor s13
32. Removal of aircraft13
.... 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 clothing14
36. Final monitoring check14
37. Read individual dosimeters14
Chapter Ill. CRITIQUE OF THE EXERCISE
38. Critique session15
APPENDIX I. Equipment17
APPENDIX II. Glossary21
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
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
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
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
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
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