The most important things to MBI’s customers are safety and security. While these are an absolute must, it is also imperative that these buildings meet the required building codes, as well as provide customers with the necessary compliance required by its industries regulatory agencies.
MBI maintains certain certifications to ensure that our buildings provide the safest work environment possible, all the while meeting the necessary building codes. The following are a list of some of MBI’s certifications and the codes that they build to:
- American Welding Service Certification
- Canadian Welding Bureau Certification
- International Building Code (IBC 2006)
- National Electrical Code (NEC 2008)
- Canadian Standards Association
- NFPA 72
- NFPA 101
- NFPA 496
MBI’s protective building systems are specifically designed, engineered, and manufactured to allow our customers to be completely compliant with API RP 752/753. MBI also realizes that because of the safety and security nature of its products, and the fact that many of its customers use MBI products as a line of defense; all MBI buildings are also compliant with OSHA’s Mechanical Integrity requirements. Below is a summarization of each. These summaries are direct references to API’s RP 752/753, and are for your education only. Please refer directly to API RP 752 and API RP 753 for specific guidance in your decision making processes.
Click here for information on the following:
- API RP 752
- API RP 753
- OSHA MECHANICAL INTEGRITY
These two charts depict possible effects on buildings of different types when subjected to an explosion
Summary of Possible Explosion Effects on Buildings
|Source of Explosion||Type of Explosion||Nature of Blast Wave||Possible Hazards to Building Occupants|
|Vapor cloud of flammable material||Deflagration||Moderate to high overpressure of long duration||Building response to the explosion wave, fire and combustion products, glass shards|
|Condensed phase chemical explosion||Deflagration of detonation||High overpressure of short duration||Building response to the explosion wave, projectiles, glass shards and ground shock|
|Dust cloud||Deflagration||Low to high overpressure of long duration||Fire, building response to the explosion wave, glass shards fire and combustion products|
|Release of flammable boiling liquid (BLEVE)||Physical expansion and deflagration||Moderate overpressure of long duration||Fire, combustion products, building response to the explosion wave, glass shards and projectiles|
|Rapid loss of confinement of high-pressure gas||Physical expansion||High overpressure of short duration||Building response to the explosion wave and projectiles including gas shards|
Overpressure on Various Building Types
|Building Type||Peak Side – on overpressure (PSI)||Consequences|
|Wood-frame trailer or shack||1.0||Isolated buildings overturn. Roofs and walls collapse.|
|Release of flammable boiling liquid (BLEVE)||1.5||Sheeting ripped off and internal walls damaged. Danger from falling objects|
|2.5||Building frame stands, but cladding and internal walls are destroyed as frame distorts|
|Rapid loss of confinement of high-pressure gas||1.0||Partial collapse of walls that have no breakable windows|
|1.25||Walls and roof partially collapse|
|Steel or concrete frame w/ unreinforced masonry infill of cladding||1.5||Walls blow in|
|2.0||Roof slab collapses|
|2.5||Complete frame collapse|
|Reinforced concrete or masonry shear wall building||4.0||Roof and wall deflect under loading, internal walls damaged|
|6.0||Building has major damage and collapses|
Note: Source: The Effects of Nuclear Weapons, rev, ed., Samuel Glasstone, Editor Prepared by the US Department of Defense, published by US Atomic Energy Commission
For more in-depth information on RP 752, please refer to API Recommended Practice 752 second edition, 2003.
API RP 753
Recommended Practice 753 was written with the purpose of providing guidance for reducing the risk to personnel located in portable buildings from potential explosion, fire and toxic release hazards. These are the guiding principles:
- locate personnel away from covered process areas consistent with safe and effective operations.
- minimize the use of occupied portable buildings near covered process areas
- manage the occupancy of portable buildings, especially during periods of increased risk including unit start-up or planned shut-down operations
- design, construct, install, and maintain occupied portable buildings to protect occupants against potential hazards
- manage the use of portable buildings as an integral part of the design, construction, maintenance, and operation of a facility
Methods for locating portable buildings for explosion hazards
Three zones for siting portable buildings based on external vapor cloud explosions, was established. These zones are defined by standoff distances as a function of congested volume.
Portable Building Location Guidance
Allowable Locations and Personnel for Portable Buildings Intended for Occupancy
Light Wood Trailers
|Portable buildings other than light wood trailers||Occupancy Restrictions|
|Zone 1||Not Allowed||Detailed Analysis Required||House only essential personnel|
|Zone 2||Detailed Analysis required||Detailed analysis required||No restrictions|
|Zone 3||No restrictions||No restrictions||No restrictions|
Sample Zoning Maps
For congested volumes less than 7,500 cubic ft, portable buildings intended for occupancy shall be located at a standoff distance greater than 330 ft or at a distance determined by performing a Detailed Analysis.
For congested volumes greater that 1,000,000 cubic ft a Detailed Analysis is required. This Detailed Analysis is required for any portable building in Zone 1 or Zone 2. Two methods of Detailed Analysis are Consequence Analysis and Quantitative Risk Analysis (QRA). Please refer to API RP 753 for more details on each.
Along with a Detailed Blast Analysis, a structural evaluation that demonstrates the building will provide protection to the occupants from the blast hazards should be conducted. The evaluation shall:
- Establish blast design basis loading;
- Design or assess the structure of portable buildings using established blast resistant design procedures. The ASCE 1998 is recommended for blast resistant design or assessment of portable buildings for petrochemical facilities;
- Establish design criteria in terms of the allowable structural response that are appropriate for the intended use of the building;
- Design or assess the support system of portable buildings to limit the acceleration and displacement of the building;
- Address door operability and function after the blast;
- Design or assess non-structural features of portable buildings to limit flammable vapor or smoke ingress and dislodgement of internal features
In addition to guidance provided for explosion hazards, fire risk reduction measures should be considered:
- Position emergency exits away from the nearest potential fire hazard
- Establish escape routes that lead away from nearest potential fire hazard
- Locate mustering areas away from fire hazards
- Develop emergency procedures and related training
- Use fire rated portable buildings
- Install fire protection measures (water sprays, deluge systems, etc)
Toxic Release Hazards
In addition to explosion and fire hazard guidance, considerations for toxic release hazards should be taken. Portable buildings located in areas where a toxic release can reach ERPG-3 levels should meet either of the following:
- Be designed for shelter-in-place, or
- Have an emergency response plan that includes the following:
- Evacuation plan that directs personnel to a designated “shelter-in-place” or specified assembly area
- Plan to account for occupants
- Personal protection equipment (PPE) to be used by all occupants during the evacuation if required.
Portable buildings used for Shelter-In-Place should have the following features at a minimum:
- Heating, ventilation and air conditioning systems (HVAC) capable of rapid shutdown of the system or placement in recirculation mode, whichever is more appropriate. This HVAC shutdown response should be included in the emergency response plan
- Exhaust fans and duct penetrations of exterior surfaces equipped with a positive seal against infiltration of outside air
- Emergency communications equipment
- PPE to be used by all occupants during the evacuation as necessary
- Seals for windows and doors that are present
Please remember that this information is a summary of the original API RP 753, and has been provided for your education only. Please refer to API Recommended Practice 753 for full details and guidelines.
OSHA MECHANICAL INTEGRITY
MBI is strongly focused on providing the safest products on the market. Along with its focus on safety, MBI focuses on providing fully compliant buildings to its customers. Taking into consideration that a large portion of the industry deems our products as critical safety equipment and lines of defense, we provide the required documentation for OSHA Mechanical Integrity. MBI provides a Manufacturer’s Data Report with all buildings. This one page document summarizing all the specifications of the building is fully supported by a comprehensive customer data package consisting of professionally stamped engineering structural drawing and calculations; all material traceability documentation, material tests and non-destructive test reports, MSDS sheets, etc.; and all fabrication certifications, including welding and construction process documentation.
With PSM Rule, 29 C.F.R. 1910.119, and its MI provision, 29 C.F.R. 1910.119(j), and its application to structures housing employees near hazardous process operations, it is interpreted that these structures must have MI-compliant blast resistant protection.
For process equipment, including structures housing employees near hazardous process operations, the PSM Rule requires that employers document the methods and materials of construction, including adequate engineering. The PSM Rule “contains requirements for preventing or minimizing the consequences of catastrophic releases of toxic, reactive, flammable, or explosive chemicals,” including “toxic, fire, or explosion hazards.” 29 C.F.R. § 1910.119. It requires that employers compile “written process safety information,” including “information pertaining to the equipment in the process.” Id. § 1910.119(d). Employers must include information on such aspects of equipment as: “[m]aterials of construction,” “[v]entilation system design,” “[d]esign codes and standards employed,” and “[s]afety systems.” Id. § 1910.119(d)(3)(i). In addition, employers “shall document that equipment complies with recognized and generally accepted good engineering practices.” Id. § 1910.119(d)(3)(ii).
On top of these requirements, for equipment that is “critical to process safety,” OSHA imposes even stricter rules under its MI provision. For such critical equipment, employers “shall establish and implement written procedures to maintain the on-going integrity of process equipment.” Id. § 1910.119(j)(2). They must inspect and test covered equipment, following recognized and generally accepted good engineering practices.” Id. § 1910.119(j)(4). Employers must document “each inspection and test” with specific, detailed information. Id. § 1910.119(j)(4)(iv). They must ensure that new equipment “as it is fabricated is suitable for the process application for which they will be used.” Id. § 1910.119(j)(6)(i). They must also “assure that equipment is installed properly and consistent with design specifications and the manufacturer’s instructions.” Id. § 1910.119(j)(6)(ii).
The Rule thus requires employers installing a building that houses workers near hazardous process equipment, such that the building is critical to process safety, to ensure that the building is blast resistant (i.e., “suitable” for the process application) and meets generally accepted good engineering practices (i.e., actually blast resistant as needed for such an installation), has documented manufacturing inspections and tests (such as tests of welding performed), and has suitable fabrication for installation near such a significant explosion, fire, or toxic release hazard (including actually featuring blast resistance and having documentation of such details as the grade and origin of steel and other components used).
Some who claim ambiguity and question whether the Rule requires MI-compliant blast resistance in such structures have suggested erroneously that the six types of process equipment enumerated in the MI provision constitute an exclusive list and that MI requirements apply to no other equipment. The regulatory history is clear, however, that this list is not exclusive and that the MI provision covers all process equipment that is “critical to process safety.” The preamble to the Rule published in the Federal Register, subsequent OSHA letters of interpretation (which address process safety equipment generally but not, to date, blast resistance in particular), and the Rule’s Appendix all make clear that the six types of equipment listed in the Rule (pressure vessels and storage tanks, piping systems and components, relief and vent systems, emergency shutdown systems, controls, and pumps) are always considered critical to process safety, Id. § 1910.119(j)(1)(i) – (vi), but they are not the only equipment covered by MI requirements. The preamble to the final PSM Rule explains:
The Agency believes that there is certain equipment, critical to process safety, that is common to all processes. This is the equipment specified in proposed paragraph (j)(1). It is the position of OSHA that at least the equipment specified in proposed paragraph (j)(1) must be subject to the requirements contained in paragraph (j). However, if an employer deems additional equipment to be critical to a particular process, that employer should consider that equipment to be covered by this paragraph and treat it accordingly.
See also OSHA standard interpretation letters of Dec. 7, 1995 to Mr. J.B. Evans, Associate Director of Operational Safety and Risk Management at Union Carbide Corp.; March 23, 2000 to Ms. Lois Ferson, Manager of Standards Services at ISA; and July 11, 1994 to Mr. Joseph Schneider, Prof’l Dev. Chairman of the Cent. Fla. Section of the American Inst. of Chemical Engineers.
Moreover, the Appendix to the Rule indicates that PSM and MI requirements apply to “second line of defense” systems, which “control or mitigate hazardous chemicals once an unwanted release occurs.” The “primary and secondary lines of defense are what the mechanical integrity program needs to protect.” See 29 C.F.R. § 1910.119, App. C. Certainly, structures housing workers near hazardous process operations meet both of these definitions, as equipment “critical to process safety” and as a “second line of defense” that can mitigate releases after they occur, if the structures have adequate protection, such as MI-compliant blast resistance.
MBI provides Mechanical Integrity documentation on all buildings to ensure that both customers and their employees are protected from potentially catastrophic injury and liability.