Safely Using Hydrogen In Laboratories

GTW carries a large selection of hydrogen to Western Michigan, along with several other specialty gases. GTW often supplies hydrogen and other specialty gases to research laboratories and many other industries, so we felt it would be useful for our Western Michigan customers to be knowledgable on the safe use of hydrogen in laboratories.

With increasing costs associated with the limited helium supply, those who operate and design laboratory equipment are increasingly turning to their gas suppliers for hydrogen.  From universities, to medical research facilities, analytical laboratories, and chemical process buildings, hydrogen is used at nearly all facilities.  However, it is crucial to be aware of the risks that hydrogen storage, distribution, and use present along with the fire and safety code requirements administered by the National Fire Protection Association’s Compressed Gases and Cryogenic Fluids Code (NFPA 55) and the International Fire Code (IFC) and International Building Code (IBC).

Recent updates to NFPA 55 have altered the Maximum Allowable Quantities (MAQ) specifically established for hydrogen. These MAQ’s are distinguished for each storage area, decided by storage in either an unsprinklered or entirely sprinklered building and limited additionally based on whether the hydrogen cylinders are contained in gas cabinets or other locations. The corresponding volumes are expressed as standard cubic feet (cuft) of hydrogen at 1 atmosphere of pressure. In an unsprinklered building in which some cylinders are not stored in gas cabinets, the MAQ is limited to 1,000 cuft, whereas that number is multiplied to 2,000 cuft if all cylinders are stored in gas cabinets. Also, for sprinklered units where not all cylinders are stored in gas cabinets, the MAQ is also 2,000 cuft. That amount is multiplied to 4,000 cuft if all cylinders are stored in gas cabinets. NFPA further states limitations based on hydrogen use in control areas or utilizing outside storage, part II of this series will discuss the infrastructure requirements for compliance.

We will continue our discussion by selectively describing some of the primary areas and necessities for hydrogen installation when referring to fire-resistance rating and ventilation.Section 6.3.1.3.1 of NFPA details that for flammable gases stored or utilized in greater quanities than 250 cubic feet, a 1-hour fire resistance rated constrction will be utilized to separate the area. The compressed gas cylinders must be separated by 10’ or a fire-resistant wall; however, they need to be separated by 20’ or a fire-resistant wall having a minimum fire resistance rating of .5 hours from incompatible elements like oxygen. For places having hydrogen systems, appropriate safety placards must likewise be permanently set up.

Similarly, Section 6.16 states that use and storage areas that are indoors must be provided with ventilation, either mechanical or natural, so long as the natural ventilation is proven to be acceptable for the gas used. If using a mechanical ventilation process, the system must be operational while the building is occupied, with the rate of ventilation not reaching lower than 1 ft3/min per square foot of floor area of storage/use and being equipped with an emergency power system for alarms, vents, and gas detection. The system must also keep track of gas density to ensure sufficient exhaust ventilation. Part III of this series will discuss the rest of the NFPA 55 requirements for separation and controls.

To further explain the series discussing updates to NFPA 55 ensuring the safe employment of hydrogen in laboratories, we will elaborate on our discussion selectively explaining some of the primary areas and requirements for hydrogen installation in terms of separation and controls.Section 7.1.6.2 of NFPA 55 states that any flammable or oxidizing gases need to be separated by 20’ from each other, while section 7.1.6.2.1 declares that this distance can be limitlessly reduced when separated by a barrier constructed of noncombustible material a minimum of 5’ tall that provides a fire resistance rating of at least .5 hours.

The safe use of controls in hydrogen systems are stated by NFPA 55, IFC, & IBC, creating a slightly more nuanced requirement for compliance. Section 414.4 of the IBC demands that controls must be sufficient for the intended application, with automatic controls being required to operate fail-safe. Section 2703.2.2.1 of the IFC demands suitable materials for hazardous media, the main consequence being that 316L SS or copper piping shall be used and identified in accordance with ASME A13.1 with directional arrows every 20’. The system should also contain no concealed valves or breakable connections, using welded or copper brazed joints where the piping is concealed. NFPA 55 dictates that these brazing materials should have a melting point above 10,000°F.Aside from piping requirements, these codes also require the employment of emergency shutoff valves on supply piping at the point of use and source of compressed gas, along with backflow prevention and flashback arrestors at the point of use.

As the last section in the NFPA 55 series that details the the proper use of hydrogen in labs, we will close our explanation by explaining uses where the Maximum Allowable Quantities (MAQ’s) is less than the demand for hydrogen gas cylinders.

It is quite typical to come across installations where the demand for hydrogen is greater than the MAQ’s, typically in instrumentation employements and/or chemical reactions like hydrogenation. These are commonly found in installations using hydrogen where there is no outside storage and control to line pressures smaller than 150 PSIG is unobtainable . The NFPA 55 code in addition to the IBC and IFC requirements will allow for these volumes to be present inside a building; however, important enhancements to the building are called for, effectively demanding that a hydrogen shelter be built by the facility. The upgrades include advancements to the structure fire rating, transportation, fire detection, a limitation on the number of occupants, and a limit to the number of stories a building can have. These installations also have strict distancing requirements and floor and wall ratings as well. Although feasible, this scenario is not ideal and should be avoided if possible. A more efficient resolution would be to combine the facility’s requirements into many, smaller systems within which the compressed gas cylinders can be installed exclusively in gas cabinets.

GTW is a reliable132] supplier of hydrogen, along with various other specialty gases and specialty gas equipment to the Western Michigan area. Whether you are looking for specialty gases for use in your laboratory research, or any other industry in Western Michigan, GTW will have the products you need to complete your tasks. To find out more about GTW and our specialty gas products in Western Michigan, browse our website and catalog. We can be reached at 616-754-6120 or via email at darrengtwsupplies@yahoo.com
 
 
 
Larry Gallagher
CONCOA 
2/10/2016