BLAST RESISTANT MODULES (BRM’s)
What are Module X Solutions standard blast resistant module sizes?
MXS has standard module sizes of 12×20, 12×40, 14×40, and 14×20 for our blast resistant buildings.
How tall are your blast resistant buildings?
MXS recommends an 8-foot ceiling height inside the building. This provides for an exterior height of 11-foot. Taller designed buildings are occasionally the result of an optional scope or specification requirements.
How to determine module-size – 12×40 or a custom module-size?
The most common blast resistant module-size is 12×40. Modules can be assembled side-by-side to make larger buildings, for example, three 12×40 modules can be assembled to make a 36×40, etc.
The 12×40 module-size provides a good balance between floor-plan-usability and shipping-logistics. And the 12×40 module structure has been value-engineered to benefit from manufacturing economies of scale.
Sometimes the 12×40 module does NOT have enough room to meet the floor-plan requirements of a particular application, or, the installation site has limitations prevent using a 12×40 module-size. In these situation MXS will simply design the module-sizes to whatever sizes are required to meet the needs of the application. Using custom-sized modules does increase the cost, but not as much as you might think. The MXS manufacturing method allows for adjustable module sizes.
The structural module-size is only one-component of the building design. Please remember that there are multiple systems. Buildings are outfitted with interior-finishes, HVAC’s, electrical, plumbing, and/or mechanical-systems. Additionally the buildings may require systems for electrical-classification, gas-detection, fire-detection, to name a few. The cost of the outfitting is not related to module-size. Custom-module sizes only affects the welded steel structure itself. Therefore, once the overall building design with all the applicable outfitting is complete, the impact of a custom not really that much.
What information is needed to design the building for a particular blast load?
MXS starts the design process by asking for three blast parameters; blast-load, blast-duration, and damage response.
Blast-load is usually defined by Free-Field-Overpressure. The blast-load can also be defined with an Impulse-pressure, a reflected-pressure, and side-on-pressure (Pso), etc.
Blast-duration is the calculated time-span that the blast pressures will be present in milliseconds (ms).
The third parameter needed to complete the blast engineering calculation is Damage Response Level. The ASCE defines Damage Response Levels as high-damage-response, medium-damage-response, and low-damage-response.
What are the different damage responses?
Regardless of damage response used, building occupants will be protected from the initial blast event. Damage responses are defined by the American Society of Civil Engineers, Design of Blast-Resistant Buildings in Petrochemical Facilities:
- Low Damage Response – Localized component damage. Building can be used, however repairs are required to restore integrity of structural envelope. Total cost of repairs is moderate.
- Medium Damage Response – Widespread component damage. Building should not be occupied until repaired. Total cost of repairs is significant.
- High Damage Response – Key components may have lost structural integrity… Building should not be occupied. Total cost of repairs approaches replacement cost of building.
What damage response should we use?
Damage Response is defined by the owner/customer. The building manufacturer should not set this criterion. The owner/customer needs to identify the distance from the blast source, the criticality of the function, and the expected occupancy. Depending on the answers to these questions the owner/customer will set the required damage response for the building.
Are you able to provide a “Class I Division 2” compliant building?
MXS can provide buildings that are CID2 compliant. We can also meet other electrical-classification, safety, and pressurization requirements.
Class I Division 2 refers to an area where a potential hazard (e.g., a fire, an explosion, etc.) may exist because of the presence of flammable gases or vapors. In this circumstance, the building itself could be an ignition-source for an explosion.
Does my building need to have pressurization?
MXS can provide buildings with pressurization to meet site safety requirements.
A “Class I Division 2” building does not automatically include pressurization. Usually, the installation-site has specifications or other safety requirements stating that pressurization is required. The owner/customer must define whether pressurization is required, or not.
How is the building shipped and installed?
All buildings are shipped by truck. (Rail does not provide delivery in a timely manner, and is therefore not a viable option.) International destinations ship by ocean-freight.
Installation is completed by off-loading the building on to your site foundation from the truck using a mobile-crane. The building includes 4 lifting-lugs on the roof. Once the building is placed, connection of the utilities is required in order for the building to be ready for use.
Multi-module buildings use a patented fastening method to bolt each of the mate-lines together. After the modules are bolted together and weatherized, there will be some interior finish work needed at the mate-line to finish the flooring/walls/ceiling. After this is complete, connect the utilities and the building is usable.
Photograph by Neal Hollimon