Safely Using Hydrogen In Laboratories

A-OX Welding Supply offers a large selection of hydrogen to Sioux Falls, along with many other specialty gases. A-OX Welding Supply frequently supplies hydrogen and other specialty gases to research laboratories and various other industries, so we felt it would be beneficial for our Sioux Falls customers to be updated on the safe use of hydrogen in laboratories.

With increasing costs associated with the limited amount of helium that is available, those who operate and design laboratory equipment are beginning to turn more frequently 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.  However, it is vital to be aware of the risks that are posed through the use, distribution, and storage of hydrogen along with the fire and safety code regulations 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 altered the Maximum Allowable Quantities (MAQ) specifically established for hydrogen. These MAQ’s are identified for each storage area, decided by storage in either an unsprinklered or entirely sprinklered building and further limited 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 multiplied 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 defines limitations determined by hydrogen use in control areas or using outside storage, part II of this series will detail the infrastructure demands for compliance.

We will further our discussion by selectively describing some of the primary areas and needs for hydrogen installation in terms of fire-resistance rating and ventilation.Section 6.3.1.3.1 of NFPA details that for flammable gases kept or employed in amounts greater 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; however, they require separation by 20’ or a fire-resistant wall that has a minimum fire resistance rating of .5 hours from incompatible matters like oxygen. For places with hydrogen systems, appropriate safety signs must also be permanently affixed.

In Addition, Section 6.16 describes that storage and use areas that are inside must be ventilated either mechanically or naturally, so long as the natural ventilation has proved to be sufficient for the gas utilized. If being ventilated mechanically, the system must be operational 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 account for gas density to guarantee correct exhaust ventilation. Part III of this series will expand on the other NFPA 55 requirements for separation and controls.

To further explain the series discussing updates to NFPA 55 ensuring the safe employment of hydrogen in laboratories, we will further our discussion selectively explaining some of the main areas and requirements for hydrogen installation in regard to separation and controls.Section 7.1.6.2 of NFPA 55 states 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 space can be limitlessly lowered 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 requirement 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 demands suitable materials for hazardous media, the main ramification 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 greater than 10,000°F.Aside from piping requirements, these codes also demand 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 concluding part in the NFPA 55 series that details the the proper use of hydrogen in labs, 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 come across installations in which the need for hydrogen is larger than the MAQ’s, most often in instrumentation uses and/or chemical reactions like hydrogenation. These are commonly found in installations using hydrogen where there is no outside storage and control to line pressures lower than 150 PSIG is not achievable . The NFPA 55 code combined with the IBC and IFC requirements allows these volumes be in a building; however, significant upgrades to the building are needed, effectively dictating that a hydrogen shelter be built by the facility. These upgrades are comprised of enhancements to the structure fire rating, transportation, fire detection, a restraint on the amount of occupants, 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. 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 many, smaller systems where the compressed gas cylinders can be installed entirely in gas cabinets.

A-OX Welding Supply is a dependable132] provider of hydrogen, along with several other specialty gases and specialty gas equipment to the Sioux Falls area. Whether you need specialty gases for use in your laboratory research, or any other industry in Sioux Falls, A-OX Welding Supply will have the products you need to get the job done. To find out more about A-OX Welding Supply and our specialty gas products in Sioux Falls, browse our website and catalog. We can be reached at 605-336-1125 or via email at info@aoxwelding.com
 
 
 
Larry Gallagher
CONCOA 
2/10/2016