---
kind: "section"
citation: "33 C.F.R. § 183.516"
title: "33"
number: "183.516"
heading: "Cellular plastic used to encase fuel tanks."
url: "https://uscodex.org/cfr/33/183.516"
---

# §183.516. Cellular plastic used to encase fuel tanks.

- (a) **Cellular plastic used to encase metallic fuel tanks must—**
  - (1) Not change volume by more than five percent or dissolve after being immersed in any of the following liquids for 24 hours at 29 °C:
    - (i) Reference fuel B ASTM D 471 (incorporated by reference, see [§ 183.5](/cfr/33/183.5.md)).
    - (ii) **No.** 2 reference oil of ASTM D 471 (incorporated by reference, see [§ 183.5](/cfr/33/183.5.md)).
    - (iii) Five percent solution of trisodium phosphate in water; and
  - (2) Not absorb more than 0.12 pound of water per square foot of cut surface, measure under Military Specification MIL P-21929B.
- (b) Non-polyurethane cellular plastic used to encase metallic fuel tanks must have a compressive strength of at least 60 pounds per square inch at ten percent deflection measured under ASTM D 1621 (incorporated by reference, see [§ 183.5](/cfr/33/183.5.md)), “Compressive Strength of Rigid Cellular Plastics”.
- (c) Polyurethane cellular plastic used to encase metallic fuel tanks must have a density of at least 2.0 pounds per cubic foot, measured under ASTM D 1622 (incorporated by reference, see [§ 183.5](/cfr/33/183.5.md)), “Apparent Density of Rigid Cellular Plastics.”

## Notes

### Amendments

[CGD 74-209, 42 FR 5950, Jan. 31, 1977, as amended by CGD 77-98, 42 FR 36253, July 14, 1977; CGD 81-092, 48 FR 55737, Dec. 15, 1983; USCG-2000-7223, 65 FR 40059, June 29, 2000]

### Source

Source: CGD 74-209, 42 FR 5950, Jan. 31, 1977, unless otherwise noted.

### Authority

Authority: 46 U.S.C. 4302; Pub. L. 103-206, 107 Stat. 2439; and Department of Homeland Security Delegation No. 0170.1, para. II, (92)(b). Subpart E is also authorized by Pub. L. 114-120, 130 Stat. 27

### Source

Source: CGD 72-61R, 37 FR 15782, Aug. 4, 1972, unless otherwise noted.

### Amendments

[CGD 74-209, 42 FR 5950, Jan. 31, 1977, as amended by CGD 77-98, 42 FR 36253, July 14, 1977; CGD 81-092, 48 FR 55737, Dec. 15, 1983; USCG-2000-7223, 65 FR 40059, June 29, 2000]