Codes can't cover 'em all
Building or buying a code-compliant hazardous material storage building typically involves working with a variety of organizations that write and enforce building and storage codes. Your storage building is often the result of a combination of hazmat storage rules and facility requirements from a variety of sources applied with consideration to your material and personnel requirements.
State and local authorities will have their own requirements for the facility and its approval and which codes they apply. Assuming the relevant portions of each of these documents is found, attempting to combine them into a practical solution can lead to building requirements that are often vague, impractical, and sometimes contradictory.
Conflicts and contradictions
Oftentimes the application of a code is in direct conflict with the requirements of a product. For example, suppose a product must be kept cool, say at 68°F, but IFC 2003 3405.3.7.5.11 requires continuous ventilation.
This means spending thousands of dollars on explosion-proof HVAC equipment only to pump the cooled or heated air out of the building at a rate of at least one CFM per minute per square foot of building (Chapter 27 International Fire Code). This is particularly challenging because a product’s temperature requirements are firm and exhaust is needed to avoid the buildup of dangerous fumes.
However, careful evaluation of the quantities of material and use in the building - for example, storage in closed containers only instead of dispensing - could lead to intermittent instead of constant exhaust. Developing an HVAC system that is as efficient as possible and an exhaust that is as small as possible can help alleviate an inefficient and energy-wasting storage requirement.
If a building has heating or air conditioning, the National Electrical Code, 2008 Edition2 NFPA 70, 210.63 will require a service outlet located within 25 feet of HVAC to fix a broken air conditioner or heater.
The intent of this code is to limit the length of cord service personnel might use to service an outbuilding and make power available where it is needed. If an outlet is going to be placed inside the hazardous material storage area, it will need to be Class I Division I explosion-proof. This will limit the tools or devices that can be plugged into it. However, if the outlet is outside the door and general duty (non-explosionproof) there is nothing to stop a maintenance technician who is unfamiliar with the hazmat storage area from plugging into that receptacle with a standard non-EP drill and running the cord through the door into a potentially explosive environment. Here is an example where the code can’t solve all ills, and common sense and proper training must take over.
While the receptacle issue may seem minor, the point isn’t that this is bad code, only that rules can’t be created to stop every possible scenario. This also points out one of the major problems in hazmat building code interpretation - often the codes being applied to the hazmat building were developed for housing or standard commercial building applications where the threat of explosion may not be an issue.
Suppose a facility is located in Bangor, Maine, and although the factory insurer has insisted on removal of flammables from the facility, the forklift operators are not happy about driving out into the snow to get the material. The goal is to put the building outside but as close to the facility as possible. The project team could consider a four-hour fire-rated building and construction that can be placed right next to the facility, but that can get expensive.
Suppose the goal is to place the drum-storage building as close to the factory as possible, but buy or build one that does not require a fire rating at all (i.e. noncombustible construction). Consultation of NFPA 30 2008, table 14.5.23 indicates that a locker of 100 to 500 SF can be placed ten feet away from an “important building on the same site” before it requires a fire rating. The International Building Code 2006 Table 6024 says that an H Occupancy structure needs to be 30 feet away to be non-combustible construction. Older versions of Factory Mutual 6049 placed the distance for non-combustible at 75 feet, but more recent versions defer to other codes.
The proper fire rating and the proper location are particularly critical issues when designing a hazmat storage facility. With this in mind and given the contradiction from major codes, it is important to consult your Local Authority Having Jurisdiction (LAHJ) about location-related issues.
Work with your LAHJ
The examples above illustrate just a few of the many, many “gray areas” or outright contradictions that can be found in the codes as you develop your plans for an outdoor hazmat storage building. The fire marshal or code compliance officer is often the final authority to take complex or contradictory code application issues and turn them into real-life solutions for safe storage.
Before a building is constructed or a pre-engineered hazmat building is purchased, it is important to consult the LAHJ with a complete list of chemicals and quantities in hand and a proposed location for the new hazmat facility. The process may seem intimidating and time-consuming, but it will save many headaches down the road.
1 2003 International Fire Code 3405.3.7.5.1 Ventilation. Continuous mechanical ventilation shall be provided at a rate of not less than 1 cubic foot per minute per square foot [0.00508m3/(s ×m2)] of floor area over the design area. Ventilation system design shall comply with the International Building Code and International Mechanical Code.
2 NEC (National Electric Code) 550 – NFPA (National Fire Protection Association) 70 NEC 210.63 – Heating, Air conditioning and Refrigeration Outlet – A 125 volt single phase, 15 or 20 amp rated receptacle outlet shall be installed at an accessible location for servicing of heating, air conditioning, and refrigeration equipment. The receptacle shall be located on the same level and within 7.5m (25 feet) of heating, air conditioning, and refrigeration equipment.
3 NFPA (National Fire Protection Association) 30, 2008, Table 14.5.2: Designated Sites.
4 International Building Code 2006, Table 602: Fire-resistance rating requirements for exterior walls based on fire separation distance.