Safely Using Hydrogen In Laboratories

Toll Company supplies a large selection of hydrogen to Minneapolis, along with various other specialty gases. Toll Company quite often supplies hydrogen and other specialty gases to research laboratories and many other industries, so we felt it would be helpful for our Minneapolis customers to be updated on the safe use of hydrogen in laboratories.

With increasing costs related to the limited volume of available helium, those tasked with operating and designing laboratory equipment are beginning to turn more frequently 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.  Still, it is extremely important to understand the risks that conincide with the storage, distribution, and use of hydrogen along with the fire and safety code requirements controlled 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 redefined 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 completely sprinklered building and further limited 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 cylinders are stored in additional areas rather than simply gas cabinets, the MAQ is bounded to 1,000 cuft, whereas that amount 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 number is increased to 4,000 cuft if all cylinders are stored in gas cabinets. NFPA further states limitations determined by hydrogen use in control areas or using outside storage, part II of this series will explain the infrastructure needs for compliance.

We will elaborate on our discussion by selectively describing some of the primary areas and necessities for hydrogen installation in regards to fire-resistance rating and ventilation.Section 6.3.1.3.1 of NFPA states that for flammable gases stored or employed in amounts greater than 250 cubic feet, a 1-hour fire resistance rated constrction shall be used to separate the area. The compressed gas cylinders must be separated by 10’ or a noncombustible wall; yet, they must be separated by 20’ or a fire-resistant wall containing a minimum fire resistance rating of .5 hours from incompatible materials like oxygen. For places containing hydrogen systems, necessary safety signs must be permanently placed as well.

Additionally, Section 6.16 declares that indoor storage and use areas 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 mechanical ventilation, the system must operate while the building is occupied, with the rate of ventilation being at a minimum of 1 ft3/min per square foot of floor area of storage/use and being armed with an emergency power system for alarms, vents, and gas detection. The system must also account for gas density to ensure proper exhaust ventilation. Part III of this series will detail the rest of the NFPA 55 requirements for separation and controls.

In continuing the series detailing updates to NFPA 55 ensuring the safe employment of hydrogen in laboratories, we will further our discussion selectively explaining some of the primary areas and requirements for hydrogen installation in reference to separation and controls.Section 7.1.6.2 of NFPA 55 dictates that any flammable or oxidizing gases need to be separated by 20’ from each other, while section 7.1.6.2.1 dictates that this length can be limitlessly lowered 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 calls for suitable materials for hazardous media, the main consequence being that 316L SS or copper piping shall be employed 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 requires that these brazing materials should have a melting point greater than 10,000°F.Aside from piping requirements, these codes also call for 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 conclude our discussion by describing applications where the Maximum Allowable Quantities (MAQ’s) is less than the demand for hydrogen gas cylinders.

It is quite typical to find installations where the demand for hydrogen is bigger than the MAQ’s, frequently in instrumentation uses and/or chemical reactions like hydrogenation. These are commonly found in installations using hydrogen where outside storage is unavailable and control to line pressures smaller than 150 PSIG is unable to be obtained . The NFPA 55 code and the IBC and IFC requirements make it possible for these volumes be in a building; however, important enhancements to the building are required, effectively demanding that the facility build a hydrogen shelter. The upgrades include advancements to the structure fire rating, transportation, fire detection, a restraint on the amount of occupants, and a building story limit. Not only this, but these installations likewise have strict requirements in regards to distancing along with floor and wall ratings. Although feasible, this scenario is not ideal and should be avoided if possible. A more effective solution would be to group the facility’s requirements into several, smaller systems where the compressed gas cylinders may be inserted completely in gas cabinets.

Toll Company is a trusted132] supplier of hydrogen, along with several other specialty gases and specialty gas equipment to the Minneapolis area. Whether you require specialty gases for use in your laboratory research, or any other industry in Minneapolis, Toll Company will have the products you need to complete your tasks. To find out more about Toll Company and our specialty gas products in Minneapolis, browse our website and catalog. We can be reached at 612-581-9889 or via email at thea@tollgas.com
 
 
 
Larry Gallagher
CONCOA 
2/10/2016