Safely Using Hydrogen In Laboratories

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

With escalating costs correlated with the limited volume of available helium, those who operate and design laboratory equipment are beginning to turn more frequently 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 extremely important to understand the risks that hydrogen storage, distribution, and use present along with the fire and safety code regulations directed 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) spelled out specifically for hydrogen. These MAQ’s are identified for each storage area, affected by storage in either an unsprinklered or completely sprinklered building and restricted further based on the hydrogen cylinders being contained in gas cabinets or not. 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 restricted to 1,000 cuft, whereas that number is doubled to 2,000 cuft if all cylinders are stored in gas cabinets. Additionally, 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 defines limitations determined by hydrogen use in control areas or employing outside storage, part II of this series will discuss the infrastructure necessities for compliance.

We will further our discussion by selectively describing some of the main areas and needs for hydrogen installation in regards to fire-resistance rating and ventilation.Section 6.3.1.3.1 of NFPA explains that for flammable gases saved or used in greater quanities than 250 cubic feet, a 1-hour fire resistance rated constrction should be employed for separation in the area. The compressed gas cylinders should be separated by 10’ or a fire-resistant wall; yet, they need to be separated by 20’ or a fire-resistant wall that has a minimum fire resistance rating of .5 hours from incompatible matters like oxygen. For areas with hydrogen systems, appropriate safety notices must be permanently placed as well.

Likewise, Section 6.16 declares that use and storage areas that are indoors must be ventilated either mechanically or naturally, so long as the natural ventilation is proven to be acceptable for the gas used. If using a mechanical ventilation process, the system must operate while the building is occupied, with the rate of ventilation being no less 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 guarantee proper exhaust ventilation. Part III of this series will detail 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 further our discussion selectively addressing some of the main areas and requirements for hydrogen installation in regard to separation and controls.Section 7.1.6.2 of NFPA 55 explains 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 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 dictated by NFPA 55, IFC, & IBC, creating a slightly more nuanced neccessity for compliance. Section 414.4 of the IBC demands that controls must be good enough for the intended application, with automatic controls being required to operate fail-safe. Section 2703.2.2.1 of the IFC requires 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 requires that these brazing materials should have a melting point higher than 10,000°F.Aside from piping requirements, these codes also call for the utilization 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 safe use of hydrogen in laboratories, we will conclude our discussion by explaining uses where the Maximum Allowable Quantities (MAQ’s) is less than the demand for hydrogen gas cylinders.

It is not unusual to find installations where the demand for hydrogen is greater than the MAQ’s, usually in instrumentation employements 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 not achievable . The NFPA 55 code combined with the IBC and IFC requirements make it possible for these volumes to be present inside a building; however, important enhancements to the building are required, effectively demanding that the facility build a hydrogen shelter. These upgrades consist of advancements to the structure fire rating, transportation, fire detection, a occupant limit, and a limit to the number of stories a building can have. Additionally, these instillations have stringent distancing regulations as well as floor and wall ratings. Although feasible, this scenario is not ideal and should be avoided if possible. A better answer would be to parcel the facility’s requirements into several, smaller systems in which the compressed gas cylinders can be installed completely in gas cabinets.

Criogas is a dependable132] distributor of hydrogen, along with many other specialty gases and specialty gas equipment to the Mexico area. Whether you are in search of specialty gases for use in your laboratory research, or any other industry in Mexico, Criogas will have the products you need to complete your tasks. To find out more about Criogas and our specialty gas products in Mexico, browse our website and catalog. We can be reached at 01-800-400-CRIO or via email at informes@criogas.com
 
 
 
Larry Gallagher
CONCOA 
2/10/2016