Safely Using Hydrogen In Laboratories

Mississippi Welders Supply Co., Inc. offers a large selection of hydrogen to Winona, along with several other specialty gases. Mississippi Welders Supply Co., Inc. frequently supplies hydrogen and other specialty gases to research laboratories and various other industries, so we felt it would be beneficial for our Winona customers to be updated on the safe use of hydrogen in laboratories.

With increasing costs associated with the limited helium supply, those tasked with operating and designing laboratory equipment are increasingly turning to their gas suppliers for hydrogen.  The use of hydrogen is found in several facilities, from medical research facilities to universities, analytical laboratories, and chemical process buildings.  However, it is imperative to be aware of the risks that are posed through the use, distribution, and storage of hydrogen along with the fire and safety code rules created 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 changed the Maximum Allowable Quantities (MAQ) spelled out specifically for hydrogen. These MAQ’s are identified for each storage area, decided by storage in either an unsprinklered or completely sprinklered building and restricted further 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 limited to 1,000 cuft, whereas that number is increased to 2,000 cuft if all cylinders are stored in gas cabinets. Also, for sprinklered units in which some cylinders are not 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 has limitations determined by hydrogen use in control areas or employing outside storage, part II of this series will detail the infrastructure needs for compliance.

We will elaborate on our discussion by selectively describing some of the main areas and necessities for hydrogen installation in terms of fire-resistance rating and ventilation.Section 6.3.1.3.1 of NFPA states that for flammable gases stored or employed in quantities larger 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 nonflammable wall; yet, they must be separated by 20’ or a noncombustible wall containing a minimum fire resistance rating of .5 hours from incompatible materials like oxygen. For locations having hydrogen systems, appropriate safety placards must be permanently placed as well.

Similarly, Section 6.16 states that storage and use areas that are inside must be provided with ventilation, either mechanical or natural, so long as the natural ventilation is verified to be adequate for the gas employed. 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 is also tasked with accounting for gas density to guarantee adequate exhaust ventilation. Part III of this series will expand on the rest of the NFPA 55 requirements for separation and controls.

To continue the series that explains updates to NFPA 55 governing the safe use of hydrogen in laboratories, we will elaborate on our discussion selectively addressing some of the important 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 must be separated by 20’ from each other, while section 7.1.6.2.1 declares that this length can be limitlessly decreased when separated by a barrier made 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 dictated by NFPA 55, IFC, & IBC, creating a slightly more nuanced need for compliance. Section 414.4 of the IBC demands that controls must be suitable 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 negative result being that 316L SS or copper piping shall be utilized 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 final installment in the NFPA 55 series governing the hydrogen’s correct use within laboratories, we will finish our analysis by explaining uses where the Maximum Allowable Quantities (MAQ’s) is less than the demand for hydrogen gas cylinders.

It is not unusual to encounter installations where the requirement for hydrogen is greater than the MAQ’s, frequently in instrumentation employements and/or chemical reactions like hydrogenation. These are frequently come across in installations using hydrogen where there is no outside storage available and control to line pressures smaller than 150 PSIG is not achievable . The NFPA 55 code and the IBC and IFC requirements will allow for these volumes to be present inside a building; however, certain building improvements are required, effectively requiring that the facility build a hydrogen shelter. These upgrades are comprised of advancements to the structure fire rating, transportation, fire detection, a restraint on the amount of occupants, and a building story limit. Additionally, these instillations have stringent distancing regulations as well as floor and wall ratings. Although doable, it is best to avoid this scenario seeing as it is not optimal. A more effective solution would be to bunch the facility’s requirements into several, smaller systems in which the compressed gas cylinders may be set up entirely in gas cabinets.

Mississippi Welders Supply Co., Inc. is a dependable132] distributor of hydrogen, along with several other specialty gases and specialty gas equipment to the Winona area. Whether you are looking for specialty gases for use in your laboratory research, or any other industry in Winona, Mississippi Welders Supply Co., Inc. will have the products you need to complete your tasks. To find out more about Mississippi Welders Supply Co., Inc. and our specialty gas products in Winona, browse our website and catalog. We can be reached at (507) 454-5231 or via email at winona@mwsco.com
 
 
 
Larry Gallagher
CONCOA 
2/10/2016