Safely Using Hydrogen In Laboratories

AOC Mexico S.A. de C.V. offers a large selection of hydrogen to Mexico, along with several other specialty gases. AOC Mexico S.A. de C.V. quite often supplies hydrogen and other specialty gases to research laboratories and several other industries, so we felt it would be useful for our Mexico customers to be updated on the safe use of hydrogen in laboratories.

With rising costs correlated with the limited amount of helium that is available, those who operate and design laboratory equipment are progressively turning to their gas suppliers for hydrogen.  Hydrogen is used in a wide array of facilities from analytical laboratories to universities, medical research facilities, and chemical process buildlings.  Nonetheless, it is crucial to be cautious of the risks that are posed through the use, distribution, and storage of hydrogen along with the fire and safety code rules 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 changed the Maximum Allowable Quantities (MAQ) specifically established for hydrogen. These MAQ’s are identified for each storage area, affected by storage in either an unsprinklered or entirely sprinklered building and restricted further based on whether or not the hydrogen cylinders are being contained in gas cabinets. 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 doubled to 2,000 cuft if all cylinders are stored in gas cabinets. Also, for sprinklered buildings 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 has limitations defined 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 principal 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 kept or utilized in quantities larger 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 noncombustible wall; however, they require separation by 20’ or a noncombustible wall having a minimum fire resistance rating of .5 hours from incompatible matters like oxygen. For areas containing hydrogen systems, necessary safety notices must likewise be permanently set up.

Similarly, Section 6.16 declares that use and storage areas that are indoors must be given either natural or mechanical ventilation, so long as the natural ventilation is verified to be adequate for the gas employed. If being ventilated mechanically, the system must function 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 guarantee sufficient 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 important areas and requirements for hydrogen installation in regard 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 decreased when separated by a barrier comprised 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 need 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 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 above 10,000°F.Aside from piping requirements, these codes also require 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 hydrogen’s correct use within laboratories, 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 encounter installations where the demand for hydrogen is greater than the MAQ’s, usually in instrumentation uses and/or chemical reactions like hydrogenation. These are often encountered in installations using hydrogen where there is no outside storage and control to line pressures lower than 150 PSIG is unobtainable . The NFPA 55 code and the IBC and IFC requirements allows these volumes be in a building; however, important enhancements to the building are needed, effectively requiring that the facility constructs a hydrogen shelter. These upgrades are comprised of enhancements to the structure fire rating, transportation, fire detection, a occupant limit, 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. While this is possible, this is not the best situation and should be averted when possible. A more efficient resolution would be to parcel the facility’s requirements into several, smaller systems where the compressed gas cylinders may be inserted entirely in gas cabinets.

AOC Mexico S.A. de C.V. is a dependable132] distributor of hydrogen, along with several other specialty gases and specialty gas equipment to the Mexico area. Whether you require specialty gases for use in your laboratory research, or any other industry in Mexico, AOC Mexico S.A. de C.V. will have the products you need to carry our your operations. To find out more about AOC Mexico S.A. de C.V. and our specialty gas products in Mexico, browse our website and catalog. We can be reached at 818-647-7427 or via email at herrmann@aoc.com.mx
 
 
 
Larry Gallagher
CONCOA 
2/10/2016