---
kind: "section"
citation: "49 C.F.R. § 179.16"
title: "49"
number: "179.16"
heading: "Tank-head puncture-resistance systems."
url: "https://uscodex.org/cfr/49/179.16"
---

# §179.16. Tank-head puncture-resistance systems.

- (a) **Performance standard.** When the regulations in this subchapter require a tank-head puncture-resistance system, the system shall be capable of sustaining, without any loss of lading, coupler-to-tank-head impacts at relative car speeds of 29 km/hour (18 mph) when:
  - (1) The weight of the impact car is at least 119,295 kg (263,000 pounds);
  - (2) The impacted tank car is coupled to one or more backup cars that have a total weight of at least 217,724 kg (480,000 pounds) and the hand brake is applied on the last “backup” car; and
  - (3) The impacted tank car is pressurized to at least 6.9 Bar (100 psig).
- (b) **Verification by testing.** Compliance with the requirements of [paragraph (a)](#a) of this section shall be verified by full-scale testing according to appendix A of this part.
- (c) **Alternative compliance by other than testing.** As an alternative to requirements prescribed in [paragraph (b)](#b) of this section, compliance with the requirements of [paragraph (a)](#a) of this section may be met by installing full-head protection (shields) or full tank-head jackets on each end of the tank car conforming to the following:
  - (1) The full-head protection (shields) or full tank-head jackets must be at least 1.27 cm (0.5 inch) thick, shaped to the contour of the tank head and made from steel having a tensile strength greater than 379.21 N/mm 2 (55,000 psi).
  - (2) The design and test requirements of the full-head protection (shields) or full tank-head jackets must meet the impact test requirements in [Section 5.3](/cfr/49/5.3.md) of the AAR Specifications for Tank Cars (IBR, see [§ 171.7](/cfr/49/171.7.md) of this subchapter).
  - (3) The workmanship must meet the requirements in Section C, Part II, Chapter 5, of the AAR Specifications for Design, Fabrication, and Construction of Freight Cars (IBR, see [§ 171.7](/cfr/49/171.7.md) of this subchapter).

## Notes

### Amendments

[Amdt. 179-50, 60 FR 49077, Sept. 21, 1995, as amended by Amdt. 179-50, 61 FR 33255, June 26, 1996; 66 FR 45390, Aug. 28, 2001; 68 FR 75759, Dec. 31, 2003]

### Authority

Authority: 49 U.S.C. 5101-5128; 49 CFR 1.81 and 1.97.

### Source

Source: 29 FR 18995, Dec. 29, 1964, unless otherwise noted. Redesignated at 32 FR 5606, Apr. 5, 1967.

### Amendments

[Amdt. 179-50, 60 FR 49077, Sept. 21, 1995, as amended by Amdt. 179-50, 61 FR 33255, June 26, 1996; 66 FR 45390, Aug. 28, 2001; 68 FR 75759, Dec. 31, 2003]