UN R110 has been prepared purely as documentation tool. The authentic and legally binding texts are . This document incorporates the following changes:

Revision 2 has been prepared purely as documentation tool. The authentic and legally binding texts are . This document incorporates the following changes:

Revision 3 has been prepared purely as documentation tool. The authentic and legally binding text is WP.29/2013/101. This document incorporates the following change:

Text as approved by the GRSG to introduce type-approval provisions for vehicles equipped with liquefied natural gas propulsion systems. The proposal has been prepared as a new consolidated version of UN Regulation No. 110.

Revision 3 | Amendment 1 has been prepared purely as documentation tool. The authentic and legally binding text is WP.29/2014/12. This document incorporates the following change:

Proposal to introduce type-approval provisions for fuel selection systems and for “valve control at stop-start”. The former focuses on ensuring that dual fuel systems prevent fuel intended for one system from flowing into the other system. The latter would let the tank valves stay open in a commanded stop-start phase as is the case for the idling phase of vehicles not equipped with start-stop systems.

Revision 3 | Amendment 1 | Corrigendum 1 has been prepared purely as documentation tool. The authentic and legally binding text is WP.29/2018/153. This document incorporates the following changes:

In the absence of complete harmonization with ISO 11439, this proposal recommends that Table 6.4 of UN R110 should be amended by the following for CNG-1 designs:

1. Delete A.17, A.25, and A.7 since they do not match the tests specified in paragraph 7.5 on Cylinder design qualification tests
2. Add A.15 and A.6 since they do match the tests specified in paragraph 7.5 on Cylinder design qualification tests
3. Add A.24 because paragraph 6.9 on Fire protection requires all PRDs on all cylinder types to comply with A.24.

Revision 3 | Amendment 2 has been prepared purely as documentation tool. The authentic and legally binding text is WP.29/2015/13. This document incorporates the following change:

Proposal as approved by the GRSG Doc to introduce a new class of CNG components (Class 6) operating at a higher pressure.

Revision 3 | Amendment 3 has been prepared purely as documentation tool. The authentic and legally binding text is WP.29/2015/89. This document incorporates the following change:

Proposal to correct the numbering of chapter 18 following the introduction of provisions for automatic valves.

Revision 3 | Amendment 4 has been prepared purely as documentation tool. The authentic and legally binding text is WP.29/2016/13. This document incorporates the following change:

Proposal to remove the provisions for welded constructions of compressed natural gas (CNG) cylinders or metal liners, including high-strength steel CNG cylinders and consolidating the earlier proposal (from document WP.29/2015/90 that was adopted but set aside at the November 2015 WP.29 session pending the proposal on cylinder construction) to regulate the discharge direction of pressure relief devices on CNG containers.

Revision 3 | Amendment 5 has been prepared purely as documentation tool. The authentic and legally binding text is WP.29/2016/95. This document incorporates the following change:

Proposal to

1. enable the use of autonomous CNG heaters for the heating of engines before the vehicle is in service
2. allow the use of Class 0 hoses with couplings using sealing technologies other than those with a 45° cone
3. correct a typographical error in paragraph 7.1. where the reference should be to paragraph 8.22 rather than 8.21
4. remove a duplicate and contradictory reference in Annex 4A to the requirements of Class 1 pressure relief valves
5. align paragraph 2.2. of Annex 4H with paragraph 18.6.1.2. limiting the delay in switching-off of the automatic valve after stalling of the engine to two seconds (rather than five as presently in the text), and
6. include the liquefied natural gas (LNG) fuel connector provisions as specified in ISO 12617:2015.

Revision 3 | Amendment 6 has been prepared purely as documentation tool. The authentic and legally binding text is WP.29/2017/15. This document incorporates the following change:

Proposal to allow for the use of natural gas refrigeration systems to vehicles propelled by natural gas (CNG or LNG). This proposal addresses a new, environmentally friendly natural gas fuelled refrigeration system for trucks with refrigerated loads that already are propelled by natural gas. Currently paragraph 18.1.7.1 allows heating systems to be fitted on vehicles to heat the passenger compartment and/or the load area of a vehicle, however, the same provision omits cooling systems that are used on trucks for the carriage of loads requiring refrigeration.

Revision 3 | Amendment 7 has been prepared purely as documentation tool. The authentic and legally binding text is WP.29/2017/114. This document incorporates the following change:

Proposal to correct the definition of “manual valve”, including deletion of the phrase “rigidly fixed to the cylinder or tank”. The definition of the manual valve as part of the accessories fitted to the container or tank (para. 4.16.) is different from the definition specified in paragraph 4.22. The proposed editorial change aims at clarifying the text of these definitions.

Revision 4 | Amendment 1 has been prepared purely as documentation tool. The authentic and legally binding text is WP.29/2017/115. This document incorporates the following change:

Proposal to correct the definition of “manual valve”, including deletion of the phrase “rigidly fixed to the cylinder or tank”. The definition of the manual valve as part of the accessories fitted to the container or tank (para. 4.16.) is different from the definition specified in paragraph 4.22. The proposed editorial change aims at clarifying the text of these definitions.

The proposal also introduces provisions for cargo-compartment refrigeration systems connected to the compressed natural gas (CNG) and/or liquefied natural gas (LNG) system(s).

Revision 4 | Amendment 2 has been prepared purely as documentation tool. The authentic and legally binding text is WP.29/2018/22. This document incorporates the following change:

Proposal to harmonize the requirements on Compressed Natural Gas (CNG) and/or Liquefied Natural Gas (LNG) vehicles of UN Regulation No. 110 with those of the international standard ISO 11439:2013.

Revision 5 | Amendment 1 has been prepared purely as documentation tool. The authentic and legally binding text is WP.29/2018/125. This document incorporates the following change:

Proposal to clarify visibility requirements for CNG cylinders, LNG tanks, and their accessories to facilitate external inspections (e.g. for periodic technical inspection).

Revision 5 | Amendment 2 has been prepared purely as documentation tool. The authentic and legally binding text is WP.29/2019/13. This document incorporates the following change:

Proposal to require, in instances where ogive protective covers are fitted to a cylinder, that the covers be removed before conducting the impact damage (drop) test. The proposal further would amend and clarify the need for a gas flow adjuster under UN R110 with regard to the use of carburetors and fuel injectors. A gas flow adjuster is not necessary when an electronic fuel injection system manages the air/fuel mixture and therefore should be removed from paragraph 18.3.1. An adjuster is needed when air/fuel mixture runs via a carburetor and therefore should be added to paragraph 18.3.2.

Revision 5 | Amendment 3 has been prepared purely as documentation tool. The authentic and legally binding text is WP.29/2019/16. This document incorporates the following change:

Proposal to introduce requirements for CNG compressor and CNG accumulator components designed to maintain stable pressure in fuel systems and to allow the use of a generator fueled by the vehicle gaseous fuel system that provides electricity to run accessories (e.g., overnight power in sleeper cabs, to maintain battery charge during high electrical power use with loading or lifting equipment).

Revision 6 | Amendment 1 has been prepared purely as documentation tool. The authentic and legally binding text is WP.29/2020/20. This document incorporates the following change:

Proposal to clarify provisions for periodic testing and periodic requalification of Compressed Natural Gas (CNG) cylinders and Liquefied Natural Gas (LNG) tanks.

Revision 6 | Amendment 2 has been prepared purely as documentation tool. The authentic and legally binding text is WP.29/2020/21. This document incorporates the following change:

Proposal to introduce changes/additions in the Change of Design Table to better specify appropriate test requirements for CNG cylinders with composite materials and, in some cases, to harmonize with International Standard Organisation (ISO) standard 11439.