Ground Based Fuel Tank Inerting

1
Pack Bay Oxygen Depletion due to OBIGGS Leaking
William CavageAAR-440 Fire Safety BranchWm. J.
Hughes Technical CenterFederal Aviation
Administration
International Systems Fire Protection Working
GroupCAA House London, England UK June 23-24,
2005
2
Planned Research

• To support potential future OBIGGS certification,
  Fire Safety Research wants to study the effect of
  large NEA leaks from an OBIGGS in a bay on the
  depletion of oxygen in the bay and surrounding
  areas
• Use the 747SP ground test article and FAA OBIGGS
  to study problem in 747 pack bay
• Instrument pack bay with 8 oxygen gas samples
  (two in each bay) as well as 2 additional movable
  samples
• Mainly concerned with injury to ground service
  and maintenance personnel
• Study the effect of purity and size ( of ASMs
  being used) of leak, the effect of opening doors
  and panels, and the difference in system running
  and not running

3
747 Pack Bay Gas Sample Locations
x
x
x
x
x
x
OBIGGS Location
x
x
- Fixed gas sample location
X
4
Table of Potential Tests
Test NEA Number of ASMs Test Description
1 8 6 Run System Until Pack Bay O2 Stabilizes Open Pack Bay 3 with OBIGGS Off
2 4 6 Run System Until Pack Bay O2 Stabilizes Open Pack Bay 4 with OBIGGS Off
3 4 3 Run System Until Pack Bay O2 Stabilizes Open Pack Bay 4 with OBIGGS On
4 4 1 Run System Until Pack Bay O2 Stabilizes Open Pack Bay 2 with OBIGGS Off
5 2 3 Run System Until Pack Bay O2 Stabilizes Open Pack Bay 1 with OBIGGS Off
6 4 3 Additional Data . . .