GB/T 31037.1-2014Fuel cell power system used for industrial lift truck applications - Part 1: Safety (English PDF)

1.1 Overview

This Part of GB/T 31037 specifies the safety requirements and safety precautions involved in the construction, identification and performance tests of the fuel cell power system used for industrial lift truck applications.

Fuel cell power systems that power electric industrial lift trucks for indoor or outdoor use include fuel cell power systems (referred to as power systems) and energy storage modules. An energy storage module refers to an electrical energy storage device that is used to start a power system, or to help or supplement a fuel cell power system to power internal or external loads. It consists of a lead-acid battery, a nickel-metal hydride battery, a lithium-ion battery, a super capacitor, or other energy storage modules with corresponding functions. This Part covers only the safety requirements of the fuel cell power system and does not include energy storage modules.

The industrial lift trucks involved in this Part include: counterbalanced fork lift truck, reach truck, straddle truck, pallet-stacking truck, platform truck, truck with elevatable operation position, side-loading truck, rough terrain truck, lateral stacking truck (both sides), lateral and front stacking truck, stacking high-lift straddle carrier, pallet truck, platform and stillage truck, non-stacking low-lift straddle carrier, and order picking truck.

This Part is applicable to proton exchange membrane (PEM) fuel cell power systems that use gaseous hydrogen as the fuel and air as the oxidant.

Hydrogen storage devices suitable for use in this Part include:

- fixed or replaceable;

- refillable or disposable;

- integrated or installed on power systems or industrial lift trucks.

This Part only considers dangerous situations that may cause injury to people, objects or the environment outside the fuel cell power system, and proposes safety requirements for such dangerous situations, excluding the safety used to filter and regulate the pressure of the oxidant (air) input to the power system, then deliver oxidant (air) to the fuel cell module.

- Thermal management system: It includes, but is not limited to radiators and associated fans, piping, circulating fluid pumps, valves, sensor devices, cooling fluid storage and replenishment tanks, etc., which can be used to keep the power system operating within the manufacturer specified operating temperature range by heating or cooling or heat removal.

- Humidifying system: A device for humidifying fuel and oxidant (air) to increase relative humidity.

- Water treatment system: It includes, but is not limited to piping, circulating water pumps, valves, sensor devices, water storage and replenishment tanks, etc. When water generated by the power system is used for humidifying fuel or oxidant or other uses, the particles and metal ions that are harmful to the power system shall be removed.

- Control system: It consists of sensor devices, circuits, actuators, control devices, and software programs that are necessary for regulation and monitoring, so that the power system’s operating parameters are able to be kept within the manufacturer’s given limits without human intervention, thus ensuring the normal operation of the power system.

- Power regulating system: It includes, but is not limited to DC / DC or DC /

AC, circuits, etc. The output power of the fuel cell stack will, by regulating current and voltage according to the requirements for the power required for the internal device of the power system and the external output power, provide the power output that meets the requirements of use.

- Ventilation system: A system that achieves air exchange inside and outside the power system through forced or natural means.

- Fuel cell power system: It consists of all or part of the components in the schematic diagram for the boundary of the power system, and is combined with an energy storage module to form a fuel cell dynamic system.

According to its different structures, it can be divided into two types: all-in- one and integrated:

lambda All-in-one system: All the components of the power system are loaded into one shell as an integral whole; the display and control interface or function buttons can be installed in the place where the operator can conveniently operate according to the actual situation.

lambda Integrated system: All the components of the power system are dispersedly installed on an industrial lift truck in accordance with the structural space and the center of gravity of the industrial lift truck.

However, all the components are connected together through circuits

GB 17799.3-2012 Electromagnetic compatibility (EMC) -- Generic standards

-- Emission standard for residential, commercial and light-industrial environments

GB 17799.4-2012 Electromagnetic compatibility (EMC) -- Generic standards

-- Emission standard for industrial environments

GB/Z 18333.1-2001 Lithium-ion batteries for electric road vehicles

GB/T 18384.3-2001 Electric vehicles -- Safety specification -- Part 3:

Protection of persons against electric hazards

GB/T 20042.1-2005 Proton exchange membrane fuel cell -- Terminology

GB/T 20801 (all parts) Pressure piping code -- Industrial piping

GB/T 20972.1-2007 Petroleum and natural gas industries -- Material for use in H2S-containing environments in oil and gas production -- Part 1: General principles for selection of cracking resistant materials

GB/T 24499-2009 Technology glossary for gaseous hydrogen, hydrogen energy and hydrogen energy system

GB/T 24549-2009 Fuel cell electric vehicles -- Safety requirements

GB/T 28816-2012 Fuel cell -- Terminology

HB 5067 Test method for hydrogen embrittlement evaluation of plating processes

ISO 15916 Basic considerations for the safety of hydrogen systems

ISO 17268.2-2006 Compressed hydrogen surface vehicle refuelling connection devices

3.1 Lower flammability limit, LFL

It refers to the lowest concentration of fuel in the fuel-air mixture that can be ignited by the source of ignition.

NOTE: This fuel-air mixture is flammable if the source of ignition can cause combustion, mainly depending on the fuel-air mixture ratio or composition. A critical ratio of the mixture concentration below the lower temperature changes, other effects (such as electrolytic corrosion) that occur when these materials are placed together, the effects of ultraviolet radiation, the effects of hydrogen erosion to the mechanical properties of the materials and interactions between the materials. In addition, flame- retardant materials shall be selected as far as possible.

- Non-metallic pipes and related accessories shall comply with the provisions of GB/T 5563, GB/T 15329.1, and GB/T 20801.

- Vulcanized rubber and thermoplastic rubber parts shall comply with the provisions of GB/T 3512-2001.

- Metal piping and metal fittings shall comply with the provisions of GB/T

20972.1-2007.

- Materials and components as well as structural design shall be based on the level of hazardous areas in which they are located in the power system or industrial lift truck, and shall comply with the relevant requirements of GB

3836.1-2010.

4.3 Piping system and fuel storage system

4.3.1 Overview

The materials of the piping system, fuel storage device and related accessories shall comply with the provisions of 4.2. In addition:

- the resistance to hydrogen embrittlement of hydrogen-related metal parts shall comply with the provisions of HB 5067;

- hydrogen-related rubber parts shall comply with the provisions of ISO

15916;

- easily corroded parts shall take effective measures for corrosion protection, such as corrosion protection coating;

- the piping system shall be able to withstand the pressure of 1.5 times the maximum allowable operating pressure specified by the manufacturer and pass the air tightness test specified in 5.2.

4.3.2 Piping system and its accessories

4.3.2.1 Overview

The piping system and its accessories such as fittings, etc. shall meet the following requirements:

- The maximum operating pressure and maximum operating temperature of

- Plastic or rubber pipe fittings conveying flammable gases shall be prevented from possible overheating. The minimum thermal deformation temperature of the material used shall be higher than the maximum temperature or set temperature allowed by the power system.

- Plastic or rubber materials used in hazardous areas shall have effective measures against the accumulation of electrostatic charges, such as electrical conductivity. The resistance per 1m of non-metallic piping shall not exceed 1Mohm.

4.3.2.4 Hydrogen piping and its accessories

The hydrogen piping and its accessories used shall meet the following requirements:

- The hydrogen piping in the enclosure of the power system shall be effectively secured or other effective measures shall be taken to avoid wear.

The design and structure of the hydrogen piping and its accessories shall comply with the requirements of GB/T 20801 (all parts).

- There shall be a certain gap between the discharge port of the hydrogen piping and the live parts. Under normal circumstances, it shall not be less than 50mm. When the hydrogen piping and the live parts are well fixed so that the gap is not less than 12.7mm due to displacement, the gap can be less than 50mm. Alternatively, the live parts are located on the limited current circuit, and no electrical energy is generated resulting in the danger.

The gap can be less than 50mm.

4.3.3 Fuel storage system

4.3.3.1 Hydrogen charging interface

The hydrogen charging interface shall comply with the provisions of ISO

17268.2-2006, and shall have a dust cover that can prevent the entry of dust, liquids, and contaminants, or other devices with similar functions.

The installation of the hydrogen charging interface shall meet the following requirements:

- INSTALL outside the fuel dilution boundary where flammable gases may be present. MAINTAIN a distance of at least 50mm from the live parts.

- SPECIFY the maximum charging pressure at the installation site.

- It is able to withstand a load of 670N from any direction without affecting the airtightness of the fuel storage system.

4.3.3.2 Hydrogen storage container

Hydrogen storage containers shall comply with the requirements of relevant national standards. Prior to the absence of national standards, reference may be made to relevant international standards.

If the hydrogen storage container is not installed in the enclosure of the power system, the separately installed hydrogen storage container shall have a safety protection enclosure against accidental operation and collision.

If the fuel storage container is replaceable, the connection between the fuel storage container and the power system shall be safely interlinked with the control system of the power system, so as to ensure that the fuel storage container operated by the power system does not become loose or fall off.

4.3.3.3 Overpressure (high / low) protection

The fuel storage system shall be provided with an overpressure protection device and meet the following requirements:

- The power system is in operation. When the pressure exceeds the normal operating pressure of the hydrogen storage container, it shall be able to inform the operator through the display screen or sound or light, or prompt emergency shutdown. When the pressure reaches the maximum operating pressure of the hydrogen storage container, it shall be able to automatically shut down and cut off the hydrogen supply.

- The power system is at rest. When the pressure reaches the maximum pressure that the hydrogen storage container can withstand, it shall be automatically vented to the outside through the pressure relief valve or a device with similar functions, to prevent the danger caused by excessive pressure. The location of the gas vent shall meet the requirements of

4.3.2.4.

- When the pressure is lower than the required pressure, it shall be able to inform the operator through the display screen or sound or light. According to the degree of danger, it shall be able to automatically shut down, or prompt emergency shutdown, or automatically shut down and cut off the hydrogen supply.

4.3.3.4 Shutdown function

The fuel storage system shall have both manual and automatic modes to shut off the fuel supply. When hydrogen leakage and overpressure (high / low) occur, it shall be able to shut down in time to cut off the fuel supply and meet the requirements of 4.8.

4.6.7 Other components

The connection of live parts such as indicator lights, diode lamps, switches, etc.

shall be secure, and corresponding measures shall be taken to prevent them from being subjected to possible mechanical damage, which may cause danger.

4.7 Electromagnetic compatibility

The power system shall be able to resist electromagnetic interference and operate normally in a preset environment. Furthermore, in normal operation, no electromagnetic interference above the specified level will occur.

In residential, commercial and light industrial environments, the power system shall meet the electromagnetic compatibility requirements specified in GB/T

17799.1-1999 and GB 17799.3-2012. In other industrial environments, the power system shall comply with the relevant provisions of GB/T 17799.2-2003 and GB 17799.4-2012.

4.8 Safety control and protection system

4.8.1 Overview

This Part covers only safety-related control and protection functions. The design of the control system shall be able to monitor the operating status of each functional subsystem of the power system, and shall have a protection function that can prevent the upgrade to a dangerous situation due to a single failure of the system components.

Manual control devices shall be clearly identified, and their design patterns may prevent accidental regulation and activation.

4.8.2 Startup

Only when all safety protection devices are in place and functioning, the power system can be activated and start operation. In order to ensure that the power system can start properly, appropriate interlocking devices can be used. When the hydrogen supply is cut off, the power system shall not start.

4.8.3 Shutdown

The power system shall have at least three modes of automatic shutdown, manual shutdown and emergency shutdown, and an emergency shutdown button. The emergency shutdown button shall be clearly identifiable, visible and quickly accessible. When the monitoring system detects abnormal operation, the operator shall be informed of the emergency shut-down by a warning sign such as display screen or sound or light. When the monitoring system detects abnormal operation that may cause danger, the system shall be able to shut down automatically.

the fuel storage system is cut off to supply fuel to other subsystems of the power system.

4.13 Sites of use

The sites where the power system is used include the operational sites and storage sites. In order to ensure that the above sites will not cause safety accidents due to hydrogen leakage, the following requirements shall be met:

- The sites of use cannot be a confined space, and must have air exchange with the outside world. When natural ventilation cannot meet the safety requirements of the power system in the manufacturer’s manual, mandatory ventilation measures shall be taken to meet the requirements.

- Hydrogen detectors and safety interlocks shall be installed at the sites of use. When the hydrogen concentration reaches 25% of the LFL, an audible

/ visual alarm shall be issued and a ventilator shall be activated for dilution.

- The sites of use and storage shall avoid the power supplies and sources of ignition where open fire / sparks may occur.

5.1 General requirements

The power system used for testing shall be a representative product produced by the manufacturer.

The test reference conditions are as follows: temperature: 15°C to 35°C;

atmospheric pressure: 86kPa to 106kPa.

5.2 Air tightness test

5.2.1 Air tightness test for piping, fittings and pressure-containing

members of fuel (hydrogen) and oxidant (air)

The power system starts operation according to the manufacturer’s prescribed procedures. After reaching the manufacturer specified normal operating conditions, STOP the operation, PURGE the power system, and CLOSE all gas outlets, leaving only one gas inlet, as shown in Figure 2. The temperature of the power system drops to ambient temperature. Nitrogen or helium passes through a gas pressure test device equipped with a pressure relief valve, a pressure sensor, a cut-off valve and a gas flow meter to enter the gas chamber inlet of the power system. Gradually PRESSURIZE within about 1min to the manufacturer specified maximum allowable operating pressure (110 ± 5) %.

KEEP this pressure for 30min. RECORD the gas leak rate measured by the flow meter.

5.8.3 Automatic shutdown test for fuel exhaust vent blocking

START the power system according to the manufacturer’s prescribed procedures. The power system shall be in normal operation. BLOCK the fuel exhaust vent of the power system. When the exhaust vent is over pressure due to blockage and reaches the value set by the manufacturer, the power system shall be able to meet the requirements of 4.8.5. PERFORM automatic shutdown.

CUT off the hydrogen supply source. After troubleshooting, the power system shall start normally.

5.8.4 Circuit overcurrent alarm and shutdown test

PROVIDE the power system with an overcurrent signal that exceeds 100% of the rated output current. The circuit short-circuit protection device shall start up.

Meanwhile, the control system shall immediately alert the operator through the display screen or sound or light. In addition, it shall be able to automatically cut off the total power output, or perform automatic shutdown, or prompt emergency shutdown. The power system that is cut off from the total power output or is automatically shut down shall meet the requirements specified in 4.8.7.

5.9 Interlock test for safe connection of the fuel storage container

If the power system adopts a replaceable fuel storage container, the connection between the fuel storage container and the power system shall be safely interlocked with the control system of the power system. If the fuel storage container and the power system fail to be properly connected, for instance, in a disconnected state, the power system shall not be properly started or operated, and sound and light warnings shall be provided. If the power system is in normal operation, DISCONNECT the fuel storage container from the power system.

The power system shall be able to shut down automatically and provide sound and light warnings.

5.10 Surface temperature rise test of the power system

5.10.1 Test process

The purpose of this test is to measure the surface temperature rise of the components of which the exterior surfaces may be in contact with the operator or the environment during the normal operation, for instance, the power system’s enclosure, operating lever, handle, knob, etc.

Test ambient temperature: 15°C to 35°C.

Before the test, thermocouple adhesives or high-temperature tapes shall be used to attach thermocouples to pre-selected measurement points. Meanwhile, the ambient temperature during the test shall be monitored.

The test is performed according to the following steps:

f) auxiliary power consumption;

g) size;

h) weight (weight of the power system, balance weight);

i) ambient temperature range (minimum and maximum) for expected operation of the power system, in degrees Celsius (°C);

j) heating circuit (if applicable): rated heat output, maximum flow, pressure, and temperature;

k) warnings signs for reminding potential personal injury to the staff or damage to the equipment, and installation instructions;

l) executive standard number;

m) precautions for use.

If the fuel cell power system is classified as a hazardous area category according to GB 3836.14-2000, it shall be identified accordingly.

6.3 Identification of components

The components that the user needs to contact shall be identified so that they can be checked against the drawings of the fuel cell power system in the technical data.

Warning signs shall be placed in appropriate locations. Moreover, electrical hazards, hydrogen hazards, high heat components, and mechanical hazards shall be identified.

For the control devices, visual indicators, and displays (especially those related to safety) used in the human-machine interfaces, functions shall be clearly identified on the surface or adjacent areas.