---
kind: "section"
citation: "46 C.F.R. § 108.409"
title: "46"
number: "108.409"
heading: "Location and spacing of tubing in pneumatic fire detection system."
url: "https://uscodex.org/cfr/46/108.409"
---

# §108.409. Location and spacing of tubing in pneumatic fire detection system.

- (a) All tubing in a pneumatic fire detection system must be on the overhead or within 300 millimeters (12 inches) of the overhead on a bulkhead in a location where—
  - (1) No portion of the overhead is more than 3.6 meters (12 feet) from the nearest point of tubing;
  - (2) Beams or girders extending below the ceiling or other obstructions do not detract from the effectiveness of the tubing; and
  - (3) **Damage to the tubing, is unlikely to occur if it is not protected.**
- (b) If tubing in a tubing circuit is installed in an enclosed space, at least 5% of the tubing in the circuit must be exposed in the space, except that at least 7.6 meters (25 feet) of tubing must always be exposed in the space.
- (c) A pneumatic fire detection system must be set to activate after approximately a 22 °C. (40 °F.) per minute increase in temperature at the center of the circuit in the system.

## Notes

### Authority

Authority: 43 U.S.C. 1333; 46 U.S.C. 3102, 3306; DHS Delegation No. 00170.1, Revision No. 01.4.

### Source

Source: CGD 73-251, 43 FR 56808, Dec. 4, 1978, unless otherwise noted.