Overview of API RP 99: Flash Fire Risk Assessment for Upstream Oil/Gas

Tyndale's Overview of API RP 99

Among the many dangers oil and gas worker face, flash fire explosions pose one of the most threatening risks. A flash fire is characterized by high temperature, short duration, and a rapidly moving flame front. The NFPA defines flash fire as, “A fire that spreads rapidly through a diffuse fuel, such as dust, gas or the vapors of an ignitable liquid, without production of damaging pressure (1).”

The American Petroleum Institute (API) published its Recommended Practice (RP) 99, First Edition, in April 2014. This document “provides guidance for the upstream oil and gas industry on hazard identification and risk assessment exercises to assess and mitigate the risk of human injury caused by exposure to flash fire (p. 1).” (2)

The scope of RP 99 is limited to the personnel exposed to the risk of hydrocarbon-based flash fires in the upstream exploration and production sector of the oil and gas industry. This sector includes oil and gas production, drilling, well bore (or servicing) operations, and gas processing prior to interstate pipeline transportation (p. 1)(2). API’s RP 99 specifically focuses on flash fires that result from the unexpected ignition of hydrocarbon vapors.

“Do No Harm” Flame Resistant Clothing (FRC) 

API’s RP 99 defines FRC as “apparel designed by the manufacturer to not increase the extent of injury experienced by the wearer when exposed to a hydrocarbon flash fire (p. 2).” (2) This definition is a departure from the requirements outlined in NFPA 2112, which states that garments must provide a certain degree of protection. While NFPA 2112 establishes a minimum threshold of performance, garments that meet NFPA 2112 will have different levels of protection depending on the hazard, fabric and garment.

FR clothing is considered the last line of defense, something API outlines in Figure 2 of RP 99 (p. 7). In its Hierarchy of Controls Illustration, API demonstrates that the methods at the top of the list are potentially more effective and protective (Elimination, Substitution, Engineering Controls, and Administrative Controls) than those at the bottom (PPE). “In the event other protective measures fail, garment selection and PPE offers a final layer of protection intended to lessen the severity of injury (p. 6).” (2)

Engineering and substitution, while most effective at reducing hazards, also tend to be the most difficult to implement into an existing process. The initial cost of engineering controls can be higher than the cost of administrative controls or personal protective equipment (PPE), but over the long term, operating costs are frequently lower and, in some instances, can provide a cost savings in other areas of the process.

Administrative controls and PPE are frequently used with existing processes where hazards are not mitigated with other controls. These methods for protecting workers have also proven to be less effective than other measures, requiring significant effort by the affected workers and supervisors. While FRC can minimize the severity of an injury, it does not provide complete protection from flash fire (p. 7). (2)

API’s General FRC Guidelines

Recommended Practice 99 states that the employer shall complete a risk assessment for their operations to identify and mitigate risk of flash fire injury. An alternative to documenting flash fire risk assessment is to use API’s general FRC guidelines and require FR for personnel as indicated.

Section 7 of RP 99 provides a list of activity where the industry agrees flame resistant clothing must be worn (it should be noted that many activities outlined below occur in multiple operations, and that this list provides general guidance but is not comprehensive):

  • Drilling – Drilling into a hydrocarbon bearing zone that has the potential to release hydrocarbon vapors into the atmosphere may raise the risk of flash fire.
  • Completions and Well Servicing – Such activities include: handling of flammable liquids, perforating operations through fracture operations, and close proximity to open wellbores or a frac flowback tank.
  • Gas Processing – Such activities include: close proximity to gas processing equipment and piping, opening process equipment or storage vessels that may contain hydrocarbons, and maintenance conducted on natural gas compressors.
  • Production – Such activities include: opening a thief hatch, manually lighting burners and fired equipment, venting and blowing down process equipment, and transferring liquid hydrocarbons or produced water into or out of a transport truck.
  • SimOps (or simultaneous operations) – Any combination of complex operations or high risk activities such as hot-tap and in-service welding.

*For API’s complete list, see RP 99 page 8 and 9.


In our four-part series last summer, Tyndale outlined recommendations for complying with OSHA 1910.132 flash fire memo. In March 2010, OSHA issued an Enforcement Policy Letter intended to provide insight into compliance with standard 1910.132 as it relates to protection against flash fire.

One key point Tyndale noted was that the language used in the letter referring to NFPA 2112 is suggestive. It remains unclear whether or not OSHA will require complete NFPA 2112 compliance. With the issuance of API’s Recommended Practice 99, it appears that their specifications for FRC are not requiring NFPA 2112 compliance specifically.

Did you know: Tyndale offers several styles of flash fire rated garments? When a garment is flash fire rated, it has been made from materials that have been flash fire tested according to ASTM F1930 with a three second exposure, and achieves less than 50% predicted body burn. This is the same performance specification as NFPA 2112, and garments that are flash fire rated will provide similar protection to 2112-certified garments.

Visit www.tyndaleusa.com today to learn more about our product selection for workers who face flash fire hazards.

References for this post were accessed May/June of 2014:

(1) https://www.tyndaleusa.com/blog/2013/10/25/flash-fire-basics-and-innovative-product-solutions/

(2) http://www.api.org/publications-standards-and-statistics/standards/whatsnew/publication-updates/new-exploration-and-production-publications/api_rp_99

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