July 20, 2020

Ms. Falicia Hill, Director of Safety Programs
American Tower Corporation
3500 Regency Parkway
Suite 100
Cary, NC 27518

Dear Ms. Hill:

Thank you for your letter to the Occupational Safety and Health Administration’s (OSHA) Directorate of Enforcement Programs. This letter rescinds the letter issued on July 25, 2019 to Ms. Hill, by removing the parenthetical in the second paragraph of the background section, see attachment. You have requested an interpretation regarding a possible conflict on the minimum separation distance between aboveground liquefied petroleum gas (LPG) containers and buildings in OSHA’s 29 CFR § 1910.110 – Storage and Handling of Liquefied Petroleum Gas Standard, and National Fire Protection Association (NFPA) 58 – Liquefied Petroleum Gas Code (2017 Edition). This letter constitutes OSHA’s interpretation of the requirements discussed in the letter and may not be applicable to other questions not delineated within your original correspondence.

This letter rescinds the letter issued on July 25, 2019 to Ms. Hill, by removing the parenthetical in the second paragraph of the background section, see attachment

Background: In your letter, you state (paraphrased) that NFPA 58 (2017), Sections 6.28.2¹ and 6.28.3,² allow for the minimum separation distance between aboveground LPG containers (used for stationary engines) and buildings to be one-half the distance required by OSHA’s Standard, 29 CFR § 1910.110(b)(6)(ii).³

Under 29 CFR § 1910.110(b)(6)(ii), each individual LPG container must be located within a specific distance from the nearest important building or group of buildings in accordance with Table H-23.

NFPA 58 (2017) Section 6.28.2 requires containers for stationary engines to meet the separation distance requirements in Section 6.4. NFPA 58 (2017) Section 6.28.3 includes a provision for LPG containers for stationary engines that have a fill valve with an integral manual shutoff valve to have a minimum separation distance one-half of the distance specified in Section 6.4. Section 6.4 references Table 6.4.1.1 that lists the separation distances between containers, important buildings, and adjoining property lines.

Question: Will OSHA accept NFPA 58 (2017), Sections 6.28.2 and 6.28.3, as a reduction in LPG container separation distance as being in compliance with 29 CFR § 1910.110(b)(6)(ii)?

Response: No, OSHA will not accept the reduction in LPG container separation distance specified in NFPA 58 (2017), Sections 6.28.2 and 6.28.3.

As stated in your letter, OSHA agrees that adding an engineering control (e.g., fill valve with an integral manual shutoff) may provide better isolation and may prevent flammable gas from escaping when the hose end valve is disconnected. This safeguard, however, relies on human intervention (e.g., operator closing the valve) and does not eliminate other LPG release scenarios which, when ignited, could affect a nearby building. Examples of other release scenarios include failure of a vapor withdrawal line or service valve, pressure relief valve venting, and liquid withdrawal valve failure. In addition, OSHA’s standard includes a provision for the minimum separation distance between LPG container filling connections, and combustion and mechanical air intakes, to reduce the possibility of ingesting and igniting flammable vapor inside intakes.⁴ Furthermore, OSHA’s standard includes separation distance requirements for installing fixed electrical equipment in hazardous locations to assure control of ignition sources.⁵ OSHA concludes that NFPA 58 (2017), Sections 6.28.2 and 6.28.3, do not provide an equivalent level of safety as provided by the greater separation distance (a passive mitigation measure) required in 29 CFR § 1910.110(b)(6)(ii) and Table H-23.

In addition, since you are located in North Carolina, you should be aware that the state of North Carolina operates its own occupational safety and health program, under a plan approved and monitored by federal OSHA. The North Carolina Occupational Safety and Health (NC OSH) program adopts and enforces standards and investigates safety and health concerns in workplaces throughout the State. State Plans are required to have standards and enforcement programs that are at least as effective as OSHA’s, but may have different or additional requirements.

Therefore, you may wish to contact NC OSH at:

North Carolina Occupational Safety and Health Division
1101 Mail Service Center
Raleigh, North Carolina 27699-1101
Telephone: (919) 707-7874
/stateplans/nc

Thank you for your interest in occupational safety and health. OSHA’s requirements are set by statute, standards, and regulations. Our letters of interpretation do not create new or additional requirements but rather explain these requirements and how they apply to particular circumstances. This letter constitutes OSHA’s interpretation of the requirements discussed. From time to time, letters are affected when the Agency updates a standard, a legal decision impacts a standard, or changes in technology affect the interpretation.

To ensure that you are using the correct information and guidance, please consult OSHA’s website at http://www.osha.gov. If you have additional questions, please contact the Directorate of Enforcement Programs at (202) 693-2100.

Sincerely,

Patrick J. Kapust
Acting Director, Directorate of Enforcement Programs

Enclosure

¹ NFPA 58 (2017) Section 6.28.2: Containers for stationary engines shall be installed to meet the separation requirements of Section 6.4.
² NFPA 58 (2017) Section 6.28.3: Where containers for stationary engines have a fill valve with an integral manual shutoff, the minimum separation distance shall be one-half of the distance specified in section 6.4.
³ 29 CFR § 1910.110(b)(6)(ii): Each individual container shall be located with respect to the nearest important building or group of buildings in accordance with Table H-23.
⁴ See, 29 CFR § 1910.110(b)(14)(vii).
⁵ See, 29 CFR § 1910.110(b)(18).