International Safety Standards for Hydrogen Safety that Every Battery Room Manager Should Know
Out of all the risky elements in a battery room, hydrogen is the most capable of serious damage if left unmonitored. Hydrogen tends to get outgassed by charging batteries once the charge goes above 80%. And because it’s way lighter than air, it floats upwards and starts pooling at the highest point in the room.
Not only is hydrogen highly flammable, but being colorless, odorless, and invisible, it’s also hard to detect. The good news is there are many safety standards and codes that can help you eliminate the threat of hydrogen explosions from your battery rooms. Read on to know what they are
Standards That Address Hydrogen Risks in Battery Rooms
1.International Fire Code,
The International Fire Code (IFC) contains guidelines to safeguard life and property from fire and explosion hazards. Section 608.1, specifically, deals with stationary storage battery systems used for uninterruptible power supply. In 608.6.1, the codes require adequate room ventilation to prevent unsafe concentrations of hydrogen.
To be compliant, space containing flooded lead-acid, flooded nickel-cadmium, and valve-regulated lead-acid batteries should have ventilation systems per the International Mechanical Code to limit the maximum concentration of hydrogen to 1% total volume of the room. Plus, the minimum continuous ventilation rate should be at least 1 cfm/sq ft of the floor area of the space.
2.The National Fire Protection Association (NFPA)
In the United States, codes and standards are often adopted by local jurisdictions and enforced by law. The interesting thing about National Fire Protection Association standards is that they are voluntary but still widely respected and adopted not just in the United States but throughout the world.
Created in 1896 by a group of engineers and insurance representatives, today NPFA is 50,000 members strong and still committed to protecting lives and property from fire, electrical, and related hazards.
NFPA 1 and NFPA 2 aim to minimize hydrogen hazards in battery rooms. These codes emphasize the need for ventilation and gas detectors in energy storage systems and battery locations. Let’s look at what they say in a bit more detail.
Mechanical ventilation shall be provided at a rate of not less than 1 ft3/min/ft2 (5.1 L/sec/m2) of floor area of the room or cabinet. The ventilation can be either continuous, or activated by a gas detection system in accordance with 22.214.171.124.2.
Let’s break this down in the context of hydrogen in battery rooms. According to NFPA, the LFL of hydrogen is 4%. So for the battery room ventilation system to comply with this code, it should be able to limit the concentration to 25% of LFL, which is 1% hydrogen by volume in air. This will bring down the threat of hydrogen fires and explosions significantly.
NFPA 2, Hydrogen Technologies Code, is a comprehensive set of guidelines for hydrogen storage, use, and handling. Annexure M, Para M.2.1 of the code, shares requirements for hydrogen gas detectors. According to this code, a hydrogen detector should demonstrate a minimum measurement range of 0-4% hydrogen volume in air. The recommended requirement, however, is 0% to 10% hydrogen v/v in air.
It further indicates that the sensor should have a minimum lower detection limit (LDL) of 1000 parts per million (PPM) hydrogen v/v in the air - meaning the detector should be sensitive enough to measure and quantify leak rate as low as 1000 PPM. Not only measure the sensor should also trigger a low alarm at 4000 PPM (0.4% hydrogen v/v in air) and a high alarm at 10000 PPM (1% hydrogen v/v in air).
3.The Occupational Safety and Health Administration (OSHA)
The OSHA is a federal agency that works to minimize the health and safety risks of employees in the United States. In contrast to NFPA, all employers must comply with OSHA standards. The following OSHA standard addresses hydrogen off-gassing in battery rooms through ventilation requirements.
1926.441(a)(1) mandates, “Batteries of the unsealed type shall be located in enclosures with outside vents or in well-ventilated rooms and shall be arranged so as to prevent the escape of fumes, gases, or electrolyte spray into other areas.” Meanwhile, 1926.441(a)(2) requires “Ventilation shall be provided to ensure diffusion of the gases from the battery and to prevent the accumulation of an explosive mixture.”
In other words, the placement of batteries in rooms with efficient ventilation systems is key to preventing the build-up of flammable pockets of hydrogen. In addition to ventilation, OSHA also requires every battery room to have a functional hydrogen sensor to monitor leakages.
4.IEEE Standard 450
For over a century, The Institute of Electrical and Electronics Engineers (IEEE) Standards Association has been developing industry standards and best practices to foster technological innovation while protecting public health and well-being. In 450, IEEE recommends best practices for maintenance and testing to optimize the performance and life of vented lead-acid batteries.
It recommends measurement of temperature and ventilation levels. Temperature because it impacts battery life, while ventilation allows the movement of air to minimize the risk of hydrogen concentration. The standard also requires installing hydrogen sensors to limit the build-up to permissible levels. It recommends placing them at the highest draft-free points in a confined room for accurate leakage detection.
5.International Electrotechnical Commission (IEC)
IEC is to Europe, the Middle East, and Africa, as IEEE Standards Association is to the United States and other parts of the world. The IS/IEC 60079-29-2 recommends selecting hydrogen detectors based on multiple criteria: Operating range of target gases, required accuracy, responsiveness, presence of background gases, hazard zone classification, environmental conditions, and compatibility of sensor technology with the application, to name a few. It also provides the requirements for optimal placement of sensors in confined spaces such as battery rooms.
The IS/IEC 600079-29-2 guidelines are exhaustive, and we’ll cover them in greater detail in one of our upcoming blogs.
In addition to the above codes and standards, others, like NFPA Article 64 and the National Electric Code, also stress the need for well-functioning ventilation systems and strategically-placed sensors to keep hydrogen build-ups in battery rooms in check.
Nearly all codes and standards we explored today highlight two factors to improve hydrogen safety in battery rooms: Ventilation systems to force old air out and bring new air in to keep outgassed hydrogen at 1% levels and reliable sensors located intelligently to catch leaks and trigger early alarms. In fact, measuring hydrogen leakages is the first step to prevent it from building up in a confined space such as a battery room.
At 21 Senses, we make sensors that can detect H2 at 1 PPM level, making them far more sensitive than the 4000 PPM levels most standards recommend. We also help you place them strategically at the ideal spots for early leak detection and more importantly we provide the most cost effective solution. Click here to reach out to us today.