DOC AIRBUS | AMM A320FFIRE SEALS - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
1. General
For fire protection purposes, the APU is encapsulated within the A/C. This has been accomplished by providing a dedicated compartment (designated fire zone) within the tailcone. The APU and most power plant systems are installed within this kind of compartment. Only the exhaust system and the air intake extend beyond the compartment, thus the fire wall breakthroughs incorporate additional sealing.
Therefore all components of this passive fire protection system are permanently installed in the tailcone structure or on the APU compartment access doors.
** ON A/C NOT FOR ALL For fire protection purposes, the APU is encapsulated within the A/C. This has been accomplished by providing a dedicated compartment (designated fire zone) within the tailcone. The APU and most power plant systems are installed within this kind of compartment. Only the exhaust system and the air intake extend beyond the compartment, thus the fire wall breakthroughs incorporate additional sealing.
Therefore all components of this passive fire protection system are permanently installed in the tailcone structure or on the APU compartment access doors.
2. Component Location
** ON A/C NOT FOR ALL 
Fire Seals - Component Location| ------------------------------------------------------------------------------- |
| FIN | FUNCTIONAL DESIGNATION | PANEL|ZONE|ACCESS | ATA |
| | | | | DOOR | REF. |
| ------------------------------------------------------------------------------- |
| AIR INTAKE SYSTEM FIRE SEAL 315/ 315AL/ 49-16-42 |
| 316 316AR |
| EXHAUST SYSTEM FR84 FIRE SEAL 315/ 315AL/ 49-81-41 |
| 316 316AR |
3. Description
The APU compartment consists of titanium firewalls:
The support structures are designed to give protection against the effects of a fire. The suspension system and the support structure are designed to minimize the hazards of a fire which burns through the APU casing. Below the support structures, the support brackets are made of titanium. The areas where the titanium and the aluminum-alloy touch have protection against corrosion.
Gaskets are installed:
The APU exhaust is installed externally of the fire zone (FR84 to the end of the tailcone).
Two fire seals installed around the exhaust muffler, give protection against the risk of a fire in the exhaust compartment. The front fire seal is installed around the exhaust muffler at FR84. The rear fire seal is installed in the end cover of the exhaust muffler compartment. The rear fire seal prevents an opposite flow of the exhaust gases from the APU. This prevents a subsequent overheat condition in the exhaust muffler. The compartment is ventilated through two louvers.
The APU compartment consists of titanium firewalls:
- fwd. firewall (part of FR80),
- aft. firewall (part of FR84),
- compartment ceiling,
- right and left sidewalls,
- bottom firewall (access doors 315AL and 316AR).
The support structures are designed to give protection against the effects of a fire. The suspension system and the support structure are designed to minimize the hazards of a fire which burns through the APU casing. Below the support structures, the support brackets are made of titanium. The areas where the titanium and the aluminum-alloy touch have protection against corrosion.
Gaskets are installed:
- at the cut-outs on the front firewall (FR80),
- at the cut-outs on the rear firewall (FR84),
- where the fuel lines enter the APU compartment,
- where the air ducts enter the APU compartment,
- where the electrical harness enters the compartment,
- where the exhaust muffler goes out of the compartment.
The APU exhaust is installed externally of the fire zone (FR84 to the end of the tailcone).
Two fire seals installed around the exhaust muffler, give protection against the risk of a fire in the exhaust compartment. The front fire seal is installed around the exhaust muffler at FR84. The rear fire seal is installed in the end cover of the exhaust muffler compartment. The rear fire seal prevents an opposite flow of the exhaust gases from the APU. This prevents a subsequent overheat condition in the exhaust muffler. The compartment is ventilated through two louvers.