The flameout protection device on gas appliances can be regarded as a safety device. It is used to detect the presence of a flame when the gas appliance valve is in the open state. If there is no flame signal when the valve is open, it will shut off the gas valve to ensure that there is no gas leakage.

As most people know, for domestic gas-burning appliances such as stoves and water heaters, there have long been clear requirements in their product standards:

Starting from May 1, 2008, the implementation of GB16410-2007 "Household Gas Stoves" requires that all household gas stoves must be equipped with an automatic flameout protection function. Since April 1, 2002, the implementation of GB 6932-2001 "Household Gas Instantaneous Water Heaters" mandates in Article 5.4.1 that there should be a flameout protection device or a re-ignition device. So, what are the specific regulations for flameout protection devices on commercial gas-burning appliances?

1. "Urban Gas Design Code" GB50028-2006 (2020 Edition)

10.5.3 For Commercial Gas Equipment Set in Basements, Semi-basements (except for liquefied petroleum gas), or Closed Above-Ground Rooms, the Following Requirements Shall Apply:

1. A manual quick-closing valve and an emergency automatic cut-off valve shall be provided for the gas inlet pipe. The emergency automatic cut-off valve must be in the closed position during a power outage.

2. Gas equipment shall be equipped with a flameout protection device.

3. Gas rooms shall be equipped with gas concentration detection alarms, which shall be centrally monitored and controlled by a management room.

4. Carbon monoxide concentration detection alarms should be installed where appropriate.

5. An independent mechanical ventilation system should be installed. The ventilation rate shall meet the following requirements:

1) During normal operation, the air should be changed at least 6 times per hour. During emergency ventilation, the air should be changed at least 12 times per hour. When not in operation, the air should be changed at least 3 times per hour.

2) When the required air for combustion is drawn from indoors, it shall meet the air volume required for combustion.

3) It shall meet the air volume required to remove excess heat loss from room heating equipment.

GB50028 has been in effect for quite some time and only specifies requirements for special usage scenarios. However, as technology has advanced and safety requirements have increased, the corresponding product standards have become more explicit.

2. "Commercial Gas Appliances" GB 35848-2018

5.2 General Structure

5.2.1 General Requirements

5.2.1.13 Gas appliances shall be equipped with flameout protection devices.

5.3.3 Safety Devices

5.3.3.1 Flameout Protection Devices

5.3.3.1.1 General Requirements

Flameout protection devices shall meet the following requirements:

a) The flame detector of the flameout protection device can be used with a constant pilot flame. The gas supply valve for the constant pilot flame and the gas supply valve for the main burner shall be designed in an interlocking manner. When the constant pilot flame is not ignited, the gas supply to the main burner shall not be allowed.

b) When the constant pilot flame is extinguished, the constant pilot flame and the gas supply valve to the main burner shall be simultaneously closed.

5.3.3.1.2 Thermoelectric Flameout Protection Devices

Thermoelectric flameout protection devices shall meet the following requirements:

a) Thermoelectric flameout protection devices shall comply with the provisions of CJ/T 30.

b) When the flame is extinguished, the flame detector itself malfunctions, or there is a connection failure, it shall safely shut off.

GB35848-2018 was published on February 6, 2018, and became effective on March 1, 2019, with a relatively long transition period. Strictly speaking, commercial stoves produced after March 1, 2019, must have flameout protection devices.

3. "Gas Engineering Project Specification" GB 55009-2021

As everyone knows, GB 55009-2021 is a fully mandatory standard that took effect on January 1, 2022. It explicitly requires:

6.2 Commercial Gas Appliances, Gas Equipment, and Accessories

6.2.5 Commercial gas appliances shall be equipped with flameout protection devices.

Explanation of the corresponding clauses:

6.2.5 Gas leaks, flashback, and flameout can all lead to safety accidents. Therefore, considering intrinsic safety, the standard specifies the basic safety devices that commercial gas appliances should have. The relevant technology for these safety devices is already mature.