---
title: "CS 25J1201 Fire extinguishing system materials — CS-25 · Avioverse"
description: "No material in any fire extinguishing system may react chemically with any extinguishing agent so as to create a hazard."
url: "https://avioverse.aero/regulations/easa/cs-25/subpart-j/cs-25j1201-fire-extinguishing-system-materials"
---

# CS 25J1201 Fire extinguishing system materials

Large Aeroplanes (CS-25) · CS-25 · EAR revision 26 Jan 2023

IR Implementing rule

## CS 25J1201 Fire extinguishing system materials

(a) No material in any fire extinguishing system may react chemically with any extinguishing agent so as to create a hazard.

(b) Each system component in an APU compartment must be fireproof.

\[Amdt 25/1]

IR — CS-25 · ED Decision 2005/006/R · CS-25 Easy Access Rules · EAR revision 26 Jan 2023

[All rules in SUBPART J – AUXILIARY POWER UNIT INSTALLATIONS](https://avioverse.aero/regulations/easa/cs-25/subpart-j)

Consolidated from the EASA Easy Access Rules (revision 26 Jan 2023, extracted 13 Oct 2026) for convenience. Not the official publication — verify against the Official Journal of the European Union and the EASA publications before operational use.