---
kind: "section"
citation: "46 C.F.R. § 170.245"
title: "46"
number: "170.245"
heading: "Foam flotation material."
url: "https://uscodex.org/cfr/46/170.245"
---

# §170.245. Foam flotation material.

- (a) Installation of foam must be approved by the OCMI.
- (b) If foam is used to comply with [§ 171.070(d)](/cfr/46/171.070.md?p=d), [§ 171.095(c)](/cfr/46/171.095.md?p=c), or [§ 173.063(e)](/cfr/46/173.063.md?p=e) of this subchapter, the following applies:
  - (1) Foam may be installed only in void spaces that are free of ignition sources.
  - (2) The foam must comply with NPFC MIL-P-21929B (incorporated by reference; see [46 CFR 170.015](/cfr/46/170.015.md)), including the requirements for fire resistance.
  - (3) A submergence test must be conducted for a period of at least 7 days to demonstrate whether the foam has adequate strength to withstand a hydrostatic head equivalent to that which would be imposed if the vessel were submerged to its margin line.
  - (4) The effective buoyancy at the end of the submergence test must be used as the buoyancy credit; however, in no case will a credit greater than 55 lbs per cubic foot (881 kilograms per cubic meter) be allowed.
  - (5) The structure enclosing the foam must be strong enough to accommodate the buoyancy of the foam.
  - (6) Piping and cables must not pass through foamed spaces unless they are within piping and cable trunks accessible from both ends.
  - (7) Sample specimens must be prepared during installation and the density of the installed foam must be determined.
  - (8) Foam may be installed adjacent to fuel tanks if the boundary between the tank and space has double continuous fillet welds.
  - (9) **MIL-P-21929B is incorporated by reference into this part.**
  - (10) The results of all tests and calculations must be submitted to the OCMI.
  - (11) **Blocked foam must—**
    - (i) Be used in each area that may be exposed to water; and
    - (ii) **Have a protective cover approved by the OCMI.**

## Notes

### Amendments

[CGD 79-023, 48 FR 51010, Nov. 4, 1983, as amended by CGD 83-005, 51 FR 923, Jan. 9, 1986; USCG-2003-16630, 73 FR 65203, Oct. 31, 2008]

### Authority

Authority: 43 U.S.C. 1333; 46 U.S.C. 2103, 3306, 3703; E.O. 12234, 45 FR 58801, 3 CFR, 1980 Comp., p. 277; Department of Homeland Security Delegation No. 0170.1.

### Source

Source: CGD 79-023, 48 FR 51010, Nov. 4, 1983, unless otherwise noted.

### Amendments

[CGD 79-023, 48 FR 51010, Nov. 4, 1983, as amended by CGD 83-005, 51 FR 923, Jan. 9, 1986; USCG-2003-16630, 73 FR 65203, Oct. 31, 2008]