An Intro to API RP-752 and API RP-753

There are no federal laws regulating what measures a facility needs to take to maintain a protected environment in the event of an explosion. However, the American Petroleum Institute (API) has established recommended practices (RP) that serve as guidelines on, among other topics, how to manage hazards associated with blast events. The two standards pertaining to blast-resistant buildings are API RP-752 and API RP-753. 

The following article goes into more detail on API RP-752 and API RP-753. It outlines what they cover, how they differ, and how they discuss vapor cloud explosions (VCEs).

What Are API RP-752 and API RP-753?

Established in 1919, the American Petroleum Institute is a trade association that represents all facets of the natural gas and oil industry. They promote safety and weigh in on public policy within the United States. Among their vast collection of RPs are API RP-752 and API RP-753. These standards outline procedures for permanent and portable buildings that focus on ensuring personnel are as safe as reasonably possible from fires, explosions, and the potential release of toxic hazards.

• API RP-752 was first released in 1995. It covers how to manage hazards associated with permanent structures in fixed locations. It was originally developed for use at natural gas liquids extraction and liquefaction plants, petrochemical and chemical plants, refineries, and other onshore facilities covered by the OSHA Process Safety Management of Highly Hazardous Chemicals, 29 CFR 1910.119.
• API RP-753 was first released in 2007. It covers how to manage hazards associated with portable buildings that are conventionally not constructed for blast or fire resistance.  

Some of the topics covered within these standards include:

• Personnel regulations: Personnel should be located away covered process areas when possible.
• Occupied buildings: Buildings are considered occupied if they have assigned personnel or regularly have personnel come to them. They should be designed, constructed, installed, and maintained to protect occupants against possible hazards. Additionally, the use of occupied buildings close to covered process areas should be minimized, especially during periods of increased risk (e.g., unit start-up or planned shutdown operations).
• Existing buildings: Existing buildings that fail to meet the criteria should have a proper mitigation plan documented and implemented for any issues uncovered during an evaluation for as long as they are in use.

How Are API RP-752 and API RP-753 Different?

API RP-752 and API RP-752 are highly similar. They are both meant to protect personnel against the same potential hazards—i.e., explosions, fires, and toxic contamination. The key difference between them is the type of building they cover. API RP-752 focuses on permanent buildings, while API RP-753 focuses on portable buildings. 

How Do API RP-752 and API RP-753 Cover VCE?

One of the main explosive scenarios covered in API RP-752 and API RP-752 is vapor cloud explosion (VCEs). VCEs occur when the following conditions are met: 

1. A flammable material is released.
2. The material forms a flammable cloud by mixing with air.
3. The cloud continues to grow.
4. The cloud reaches a source of ignition, such as an open flame.
5. The flames are accelerated by congestion.

Any building that carries the possibility or likelihood of encountering a VCE scenario should have its blast load calculated. This value determines how it should respond. 

Schedule Your Facility Planning Consultation With Module X Solutions Today

While API RP-752 and API RP-753 provide general guidelines on how to keep personnel safe from explosions, fires, and toxic materials in permanent and portable buildings. Your facility siting info can assist to support and develop a more targeted approach. The results of the evaluation and requirements  can uncover any problem areas where personnel safety is at risk, allowing facility owners or operators to implement appropriate solutions before an accident can occur.  Module X Solutions can further assist in guiding and ensuring you’re on the right path by taking all factors into consideration for an optimal streamlined solution.

Interested in learning about an optimal building design? The experts at MXS are here to help! Equipped with extensive experience designing and manufacturing blast-resistant buildings, our engineering team has the knowledge and skills to properly assess a solution to meet and/and or exceed your unique site and facility requirements. Contact us or request a quote to get started.