GB 5135.2-2025Automatic sprinkler system - Part 2: Wet system alarm valves, retard chamber and water motor alarm (English PDF)

Foreword

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part

1.Structure and Drafting Rules of Standardization Documents". Drafting. This document is Part 2 of GB 5135 "Automatic Sprinkler Systems". GB 5135 has the following parts published.

1.Sprinkler Heads;

2.Wet alarm valves, delay devices, and hydraulic alarm bells;

3.Water Mist Nozzles;

4.Dry Alarm Valves;

5.Deluge Alarm Valve;

6.General Valves;

7.Water Flow Indicators;

9.Early Suppression Fast Response (ESFR) Nozzles;

10.Pressure Switches;

11.Grooved Pipe Fittings;

13.Water Curtain Nozzles;

14.Pre-action device;

1 Scope

GB 5135.2-2025 is the Chinese national standard on automatic sprinkler system - part 2: wet system alarm valves, retard chamber and water motor alarm, in the field of environment and health protection, safety. It carries no /T suffix, which in the Chinese system means compliance is mandatory: a product or a practice within its scope has to meet it to be lawfully made, sold or carried out in China. It was issued on 31 October 2025 by the State Administration for Market Regulation; Standardization Administration of China, and takes effect on 1 November 2026. Classification: ICS 13.220.10, CCS C84. This page is published from the official record of the standard held by the Chinese standards administration: the identification, the dates, the classification and the issuing body are taken from there. The clause text, the tables and the numeric limits are in the document itself, which is delivered complete in English translation.

This document defines the terms and definitions for wet alarm valves, delay devices, and hydraulic alarm bells in automatic sprinkler systems, and specifies the requirements for wet alarm valves. Classification and designation, model designation, requirements, inspection rules, markings and instructions for use, packaging, transportation and storage of delay devices and hydraulic alarm bells. The corresponding experimental methods were developed. This document applies to the design, manufacture, and inspection of wet alarm valves, delay devices, and hydraulic alarm bells in automatic sprinkler systems.

2 Normative references

The contents of the following documents, through normative references within the text, constitute essential provisions of this document. Dated citations are not included. For references to documents, only the version corresponding to that date applies to this document; for undated references, the latest version (including all amendments) applies. This document.

GB 5135.11 Automatic sprinkler systems - Part

3 Terms and Definitions

The following terms and definitions apply to this document.

3.1 wet system alarm valve A one-way valve that only allows water to flow into a wet fire extinguishing system and activates the alarm of its associated components under specified pressure and flow rates.

3.2 valve disc assembly sealing assembly The main moving seal in a wet alarm valve to prevent backflow of water.

3.3 compensator An auxiliary component that can minimize the malfunction of wet alarm valves caused by fluctuations or shocks in water pressure.

3.4 Delay chamber A volumetric device that can minimize false alarms caused by fluctuations or shocks in water pressure.

11 Grooved pipe fittings

GB/T 7306 (all parts) 55° Sealing Pipe Thread

GB/T 9124.1 Steel pipe flanges - Part 1: PN series

GB/T 9124.2 Steel pipe flanges - Part