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Frequently Asked Questions

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Your Blast Resistant
design Questions,

What are your options as they relate to the blast resistant design of a Hunter building? Why is blast resistance important? How can Hunter help you create a safer working environment? Here, you’ll find answers. We’ve pulled together a high-level list of inquiries we regularly receive from our customers (and some other important information, too).

Hunter’s Frequently Asked Questions

A wide range of industries require blast-resistant buildings for work carried out in industrial areas, war zones and areas impacted by extreme weather. Blast-resistant buildings allow work to take place within blast zones, not only keeping your people and processes protected, but increasing worker productivity, as well.

Our modular approach makes it easy to upgrade existing projects to meet blast standards in a quick and cost-effective manner. Meanwhile, for new projects, a Hunter blast-resistant module offers a more efficient solution to meeting blast-resistance standards. In addition to safety standards, we offer custom designs that allow for blast-resistant structures suited to a project or facility’s unique needs. Many successful Hunter projects feature engineering and design elements which had never before been attempted.

A standard-sized Hunter building measures 12′ x 40′ (3.66 m x 12.20 m). However, we can design structures as small as a 100-square-foot  (9.29-square-meter) guard shack, up to a large multi-module complex exceeding 12,000 square feet (1,115 square meters). Certain specifications vary by region. For information about what’s available in your area, visit our Locations page.

Yes! Blast windows are available for building exteriors and blast doors alike. Hunter blast windows measure 30” x 36” (76.20 cm x 91.44 cm) and feature fixed pains. They may be combined to form a larger viewing area.

With three manufacturing facilities around the globe, Hunter will construct your modular product inside the facility closest to your structure’s final destination. Not only does this ensure quicker receipt of the finished product, but it helps to lower transportation costs, too. Our blast-resistant modular buildings are typically transported by truck to your location.

For more standard building designs, Hunter can typically deliver your structure within four weeks of your order. For custom blast-resistant building needs, delivery times will vary based on the complexity of your design. However, a custom building could be delivered within 90 days of design approval. 

Hunter modular and blast-resistant buildings feature lifting points at each corner to make for easier lifting by mobile crane. And we’re glad to tackle the work for you. Hunter Site Services is equipped to provide full-service unloading, setup and finish-out support.

Hunter modules are designed to be installed in Hazardous Area Zone 1/2 or Class 1 Div 2.

Per National Fire Protection Association (NFPA) standard 496, all Class I, II or III locations require pressurization if general purpose equipment will be utilized. Failure to adhere to this practice could allow sparks from general purpose equipment to create an occurrence. Other instances that might require pressurization may be driven by site-specific requirements.

Yes! API RP 752/753/756 guidelines dictate that a building situated inside any process area must be certified to withstand blast overpressures for that area. Hunter blast-resistant buildings are appropriately rated to meet zone requirements.

Yes! Our modular and blast-resistant buildings can (and regularly are) used for permanent applications including control rooms, operator structures, zone shops, offices and labs.

Blast-Resistant Basics: Terms You Should Know

Congested Volume (CV)
The volume, in cubic feet, of a collection of closely spaced objects that have the potential to increase flame speed to an extent to generate a damaging blast wave, such as an area populated with pipes, pumps, valves, vessels and other process equipment and supporting structures. (See API RP 753.1.7.1 and 1.7.2 for actual API verbiage.)

Damage/Response Level
Ratings established by the American Society of Civil Engineers (ASCE) to help estimate the cost of repairs and reuse after a blast-resistant building has been subject to a blast. Individuals inside the buildings remain protected at each response level. Those levels include:

  • Medium Response: Significant repairs are required due to widespread building damage. The building cannot be used until repaired, and cost of repairs is likely significant.
  • Low Response: Minor repairs from damage are needed, but the building can be used. The cost of repairs may be moderate.

The maximum airborne concentration below which it is believed that nearly all individuals could be exposed for up to one hour without experiencing or developing life-threatening health effects.

Standoff Distance
The distance from the edge of the congested zone to the edge of a portable building.

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Safer Surroundings on Every Front

Hunter blast-resistant buildings are engineered to keep your people, processes and equipment protected in even the most extreme environments.