UN R13 Supplement 1 (12 series) · UNECE Regulation No. 13 (ECE R13) — Uniform provisions concerning the approval of vehicles of categories M, N and O with regard to braking.
UN R13 — Supplement 1 to the 12 series of amendments
Base text → Supplement 1
- What changed
- For trailers, Annex 8, paragraph 2.5. now has an exception to the limit on the pressure at which the spring brakes begin to act.
- The limit does not apply if a pressure drop in the service braking system energy reservoir causes no corresponding drop in the spring compression chamber.
- Why
- The proposal aimed at resolving problems with installation of stronger spring brake actuators in trailers.
- Stronger spring compression chambers begin to be actuated at a higher pressure level, and then the current requirement of paragraph 2.5. cannot be fulfilled.
- The proposer states that the amendment has no loss of safety and considers the possibility to install stronger spring compression chambers with the valve solution.
Q1What changed1 change
Trailers: exception to the spring brake actuation pressure limit (Annex 8, para. 2.5.)
For trailers, Annex 8, paragraph 2.5. limits the spring compression chamber pressure at which the springs begin to actuate the brakes. This pressure must not be greater than the pressure after four full-stroke actuations of the service braking system. These actuations are made in accordance with paragraph 1.3. of Part A of Annex 7. This supplement adds an exception to this limit. The limit does not apply if a pressure drop in the service braking system energy reservoir causes no corresponding drop in the spring compression chamber. As before, the initial pressure is fixed at 700 kPa.
Q2Why it changed
- Proposed by
- Expert from the European Association of Automotive Suppliers
- Working party
- GRVA, 12th session (January 2022)
Reasons
The proposal aimed at resolving problems with installation of stronger spring brake actuators in trailers. The aim is a higher deceleration in emergency braking caused by a cut of the supply line between towing vehicle and trailer.
Sources (2)
“to resolve problems with installation of stronger spring brake actuators in trailers to realize higher deceleration in the case of emergency braking caused by a cut of the supply line between towing vehicle and trailer.”
“aimed at resolving problems with installation of stronger spring brake actuators in trailers to realize higher deceleration in the case of emergency braking caused by a cut of the supply line between towing vehicle and trailer.”
For the ABS function, an additional check valve between the reservoir and the spring compression chamber was installed in trailer braking systems. With this check valve, the spring compression chamber pressure stays at its initial level even when the service brake reservoir pressure drops.
Sources (2)
“To ensure the ABS function, i.e. prevent wheels from locking also at these low reservoir pressures, an additional check valve between reservoir and spring compression chamber was installed in trailer braking systems.”
“With this check valve the pressure in the spring compression chambers remains at its initial level even when the pressure in the service brake reservoir drops.”
Spring compression chambers with higher brake forces could give a higher margin of safety for the emergency brake and the parking brake. But they begin to be actuated at a higher pressure level, for example 540 kPa instead of 490 kPa. In this case, the current requirement of paragraph 2.5. cannot be fulfilled.
Sources (3)
“To ensure a higher margin of safety both for the emergency brake”
“the installation of spring compression chambers with higher brake forces could be done.”
“But these spring compression chambers begin to be actuated at a higher pressure level (e.g. 540 kPa instead of today 490 kPa). In this case the current requirement of paragraph 2.5. cannot be fulfilled.”
Without the check valve solution, the existing requirement is clearly justified and must be checked accordingly. The proposer states that the amendment takes this into account without any loss of safety. It considers the possibility to install stronger spring compression chambers together with the valve solution.
Sources (2)
“Without the described valve solution in the braking system the existing requirement in paragraph 2.5. is clearly justified and shall be checked accordingly.”
“The proposed amendment takes this into account, without any loss of safety, but considering the possibility to install stronger spring compression chambers together with the described valve solution.”
The proposer notes that Annex 7, paragraph 1.3.1. and Annex 8, paragraph 2.4. make sure that the service brake reservoir has a sufficient capacity.
Source
“To be noted that a sufficient capacity of the service brake reservoir is ensured by requirements of Annex 7 paragraph 1.3.1. and Annex 8 paragraph 2.4.”
Document trail
- 2021-11ProposalECE/TRANS/WP.29/GRVA/2022/9Proposal by the expert from the European Association of Automotive Suppliers
- —Working party adoptsECE/TRANS/WP.29/GRVA/12GRVA session report, para. 82
- 2022-04Sent to WP.29ECE/TRANS/WP.29/2022/78Text that GRVA sent to WP.29 and AC.1
- 2022-06WP.29 adoptsECE/TRANS/WP.29/1166Adopted at the 187th session (session report, para. 182)
- 2023-01-04In forceC.N.465.2022.TREATIES-XI.B.16.13UN depositary notification
Q3Who is affected
Vehicle manufacturer
- For trailers that do not meet the four-actuation limit of Annex 8, be ready to show the new exception applies.
- Update your documents that quote the trailer text of Annex 8 on the spring brake actuation pressure.
Component supplier
- If you supply trailer braking systems, tell the manufacturer if a reservoir pressure drop causes a corresponding spring chamber drop.
Technical service / Approval authority
- For trailers, check if a drop in service brake reservoir pressure causes a corresponding drop in spring compression chamber pressure.
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ⓘ This report gives advice only. It is not legal or type-approval advice.
More UN R13 change reports
- 15 series — Supplement 3
- 15 series — Supplement 2
- 15 series — Supplement 1
- 15 series — Base text
- 14 series — Supplement 4
- 14 series — Supplement 3
- 14 series — Supplement 2
- 14 series — Supplement 1
- 14 series — Base text
- 13 series — Supplement 7
- 13 series — Supplement 6
- 13 series — Supplement 5
- 13 series — Supplement 4
- 13 series — Supplement 3
- 13 series — Supplement 2
- 13 series — Supplement 1
- 13 series — Base text
- 12 series — Supplement 9
- 12 series — Supplement 8
- 12 series — Supplement 7
- 12 series — Supplement 6
- 12 series — Supplement 5
- 12 series — Supplement 4
- 12 series — Supplement 3
- 12 series — Supplement 2
- 12 series — Base text
- 11 series — Supplement 23
- 11 series — Supplement 22
- 11 series — Supplement 21
- 11 series — Supplement 20
- 11 series — Supplement 19
- 11 series — Supplement 18
- 11 series — Supplement 17
- 11 series — Supplement 16