TM 1-1500-204-23-11
(International Organization for Standardization Speci-
ication ISO 14644 Cleanrooms and Associated Con-
NOTE
trolled Environments Part 1: Classiication of Air Clean-
Care must be taken when attempting repairs in
liness). Related design information can be found
blackout conditions when deployed. Use hand
in Federal Aviation Administration s Advisory Circular
held white lights in a shelter with the doors
number AC145-6, Repair Stations for Bonded Com-
closed or covered to prevent light escaping.
posite and Bonded Aircraft Structure; ISO 14644 Part
Ply orientations, repair markings, and damage
4, Cleanroom Design and Construction; MIL-HDBK-
locations must be easily visible under blackout
1028/5 Environmental Controls Design of Cleanroom.
lighting before a repair is conducted. If
blackout lighting does not provide adequate
NOTE
visibility to conduct a repair, wait until daylight
Care must be taken when attempting repairs
to repair the aircraft.
in blackout conditions when forward deployed.
Use hand held white lights in a shelter with
(2) Lighting. Lighting intensity at the work
the doors closed or covered to prevent light
plane should be 75 foot candles or greater.
escaping. Ply orientations, repair markings,
and damage locations must be easily visible
under blackout lighting before a repair is
conducted.
If blackout lighting does not
provide adequate visibility to conduct a repair,
Graphite/carbon dust is electrically conductive
wait until daylight to repair the aircraft.
and can short out electrical and electronic
equipment. It can also corrode aluminum
(1) Lighting. Light ixtures should be recessed
aircraft structure.
or lush mounted. Lighting intensity at the work plane
should be 75 foot candles or greater.
(3) Contamination and dust control. Ade-
quate dust control equipment should be provided
NOTE
to decrease worker s exposure to contaminants and
reduce housekeeping requirements. Downdraft work
Both 120 volt (20 amp) and 240 volt (30 amp)
stations are recommended. At a minimum, portable
outlets should be available to power hot bon-
vacuums should be used during or immediately after
ders (both current and future equipment). Hot
any dust generating activity. Since carbon dust is
bonders require a lot of electricity, especially
conductive, sanding or grinding of carbon should not
for cures that require large heat blankets or
be accomplished adjacent to circuit breakers, elec-
high temperatures; therefore, each outlet that
trical shop equipment or electronics. If the carbon
will power a hot bonder must be on a sep-
workload is great enough, a separate room may be
arate circuit. In some cases, a dual-zone
justiied to prevent migration of carbon dust through-
hot bonder will have two different incoming
out the shop. If a separate room is used, locate
power cords which will need to be plugged
circuit breakers outside the room.
into outlets on separate circuit breakers.
2-13. BONDING/LAYUP AREA. Bonding and layup
(2) Enclosure. The area should be completely
areas should be located in a separate room, away
enclosed in order to restrict the movement of con-
from other maintenance activities (especially ones that
taminates into the bonding area.
produce dust, fumes, release agents or other contam-
inants). This room should be sized to accommodate
(3) Air ilters. Incoming air should be iltered
the largest removable composite part from the weapon
to reduce particulate contaminants. Filters in the air
system with additional area for movement of parts
supply system should be disposable. Multiple banks of
and personnel. To facilitate easy access, the bond-
traditional air ilters are an affordable and appropriate
ing/layup area should have both a rollup door for large
substitute for HEPA ilters; unless otherwise speciied
parts and a traditional man door for personnel. When
in system speciic technical data or by the unit.
separate rooms are not possible, the bonding/layup
Recommend MERV 11 rated ilter for the inal ilter;
section of the repair facility shall be thoroughly cleaned
such as the 3M Ultra Allergen ilter. (Note: 3M uses
prior to use; damage removal/preparation and other
a system different than the MERV system to rate
dust producing activities shall be stopped 30 minutes
their ilters, so you will not ind "MERV 11" written
prior to bonding/layup.
on the Ultra Allergen ilter, but it is equivalent to the
MERV 11).
a. Design Criteria. Bonding/layup rooms should
be designed to meet ISO Class 9 particulate count
(4) Temperature and Humidity. The area s
temperature and humidity should be controlled to
2-11
