Safely Using Hydrogen In Laboratories

Greco Gas supplies a large selection of hydrogen to Pittsburgh, along with several other specialty gases. Greco Gas frequently supplies hydrogen and other specialty gases to research laboratories and various other industries, so we felt it would be helpful for our Pittsburgh customers to be up to date on the safe use of hydrogen in laboratories.

With increasing costs associated with the limited volume of available helium, those tasked with operating and designing laboratory equipment are progressively 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.  Still, it is crucial to understand the risks that are posed through the use, distribution, and storage of hydrogen along with the fire and safety code regulations governed 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) spelled out specifically for hydrogen. These MAQ’s are discerned for each storage area, decided by storage in either an unsprinklered or fully 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 which some cylinders are not stored in gas cabinets, the MAQ is bounded to 1,000 cuft, whereas that amount is doubled to 2,000 cuft if all cylinders are stored in gas cabinets. Similarly, 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 defines limitations determined by hydrogen use in control areas or using outside storage, part II of this series will detail the infrastructure requirements for compliance.

We will extend our discussion by selectively describing some of the main areas and necessities for hydrogen installation in regards 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 should be separated by 10’ or a fire-resistant wall; but, they must be separated by 20’ or a noncombustible wall having a minimum fire resistance rating of .5 hours from incompatible materials like oxygen. For places that contain hydrogen systems, appropriate safety signs must be permanently placed as well.

In Addition, 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 has proved to be sufficient for the gas utilized. If using mechanical ventilation, the system must operate 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 having an emergency power system for alarms, vents, and gas detection. The system is also tasked with accounting for gas density to guarantee proper exhaust ventilation. Part III of this series will expand on the rest of the NFPA 55 requirements for separation and controls.

To further explain the series discussing updates to NFPA 55 regulating the proper utilization of hydrogen in laboratories, we will continue our discussion selectively addressing some of the main areas and requirements for hydrogen installation in terms of 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 dictates that this length can be limitlessly lowered 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 declared by NFPA 55, IFC, & IBC, creating a slightly more nuanced need for compliance. Section 414.4 of the IBC demands that controls must be sufficient for the intended application, with automatic controls being required to function without fail. Section 2703.2.2.1 of the IFC calls for suitable materials for hazardous media, the main negative result 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 dictates that these brazing materials should have a melting point higher than 10,000°F.Aside from piping requirements, these codes also require the use 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 about the the proper use of hydrogen in labs, we will finish our analysis by describing applications where there is a greater demand for hydrogen gas cylinders than the Maximum Allowable Quantities (MAQ’s).

It is not unusual to find installations in which the need for hydrogen is greater than the MAQ’s, usually in instrumentation employements and/or chemical reactions like hydrogenation. These are often encountered in installations using hydrogen where outside storage is unavailable and control to line pressures smaller than 150 PSIG is unobtainable . The NFPA 55 code along with the IBC and IFC requirements allows these volumes exist within a building; however, significant upgrades to the building are called for, effectively dictating that the facility build a hydrogen shelter. The upgrades include enhancements to the structure fire rating, transportation, fire detection, a occupant limit, and a limit to the number of stories a building can have. Not only this, but these installations likewise have strict requirements in regards to distancing along with floor and wall ratings. While this is possible, this is not the best situation and should be averted when possible. A more efficient resolution would be to group the facility’s requirements into many, smaller systems within which the compressed gas cylinders can be installed completely in gas cabinets.

Greco Gas is a trusted132] supplier of hydrogen, along with various other specialty gases and specialty gas equipment to the Pittsburgh area. Whether you need specialty gases for use in your laboratory research, or any other industry in Pittsburgh, Greco Gas will have the products you need to get the job done. To find out more about Greco Gas and our specialty gas products in Pittsburgh, browse our website and catalog. We can be reached at (724) 226-3800 or via email at info@grecogas.com
 
 
 
Larry Gallagher
CONCOA 
2/10/2016