~............................................................................. | HEALTH-SAFE CONDITION | | | | A HEALTH-SAFE CONDITION OCCURS WHEN THE OXYGEN CONTENT IS A | | MINIMUM OF 19.5% TO A MAXIMUM OF 23.5% BY VOLUME AT SEA LEVEL, | | AND THE VAPOR CONCENTRATIONS ARE BELOW THESE PERMISSIBLE EXPOSURE | | LIMITS: | | | ............................................................................... | | Permissible Exposure Level | | | | Total Hydrocarbons TWA [1] | Lower Explosive Level | | Fuel | (ppm) | (percent) | ............................................................................... |Aviation Gasoline | 300 | 1.0 | ...............................................................................
|Jet A | | |
|Jet A-1 | 160 | 0.7 |
|JP-5 | | |
|JP-8 | | |
2..................…..............................…...........................1
[1] TWA - Time Weighted Average
Table 203
S 942-471
(5)
Remove these items before you go into a fuel tank:
(a)
all jewelry - rings, bracelets, wrist watches etc.
(b)
matches
(c)
pocket warmers
(d)
hearings aid devices or other battery operated equipment.
S 942-472
(6)
Remove any clothes made of this material:
(a)
Wool
(b)
Silk
(c)
Nylon
(d)
Synthetic clothing.
S 942-473
(7)
Put on these approved protective clothes (Fig. 202):
(a)
Cotton or SARANEX 23P coveralls (non-sparking zippers or buttons)
(b)
Clean cotton head cover
(c)
Approved cotton or rubber gloves
(d)
Safety glasses or face shield
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú
28-11-00
ALL ú ú 04 Page 244 ú Jun 10/97
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400
MAINTENANCE MANUAL
CAUTION: DO NOT PUT ON COTTON SOCKS UNTIL YOU ARE TO GO INTO THE
_______ FUEL TANK. IF THE COTTON SOCKS ARE NOT CLEAN, YOU CAN CAUSE DAMAGE TO THE FUEL TANK.
(e)
100% cotton socks and/or fuel cell boots
(f)
Put rubber bands around your wrists and ankles to hold clothes tight.
S 492-474
(8)
Attach a safety line to the person who goes into the fuel tank.
S 942-475
(9)
Make sure the person who goes into the fuel tank and the person who watches agree on safety signals.
S 942-476
(10)
If a confined space communication system is used, attach the system.
(a)
Do a check to make sure the system operates correctly.
S 492-477
(11)
Put on the necessary respiration protection.
S 282-478
(12)
Make sure the respirator operates.
S 912-479
(13)
Do these steps if you are the observer:
(a)
Make sure the confined space entry permit is complete and approved (if this is a requirement).
(b)
Make a record that shows the time and who is inside the fuel tank.
(c)
Attach this sign at the fuel tank entry location where it can be seen: 1) CAUTION - PERSONNEL INSIDE - MOVE NO EQUIPMENT
(d)
Make sure you and the person(s) who will go into the tank agree that the checklist items are complete.
(e)
Make sure you and the person(s) who will go into the tank agree on communication signals and set a communication time interval.
(f)
Look at the filter-regulator to make sure the supplied air system operates correctly.
(g)
Keep visual contact with the fuel tank entry location.
(h)
Keep constant communication with the person(s) the fuel tank.
(i)
Look at the combustible gas indicator to make sure the air in the fuel tank is at 10% or less of the lower explosive limit.
(j)
Do not put your head in the fuel tank access hole unless you have the correct respirator on, for the condition of the tank, and there is another observer to watch you.
