7 Del. Admin. Code § 1352-B-12.0

Current through Register Vol. 28, No. 7, January 1, 2025

Section 1352-B-12.0 - Inerting Requirements for Ullage Volumes of ASTs Without a Floating Roof

12.1 General Requirements For Inerting an AST without a Floating Roof

12.1.1 All ASTs without a Floating Roof installed or erected after June 11, 2004 and containing Flammable Regulated Substances as defined by NFPA 30, or Spent Acids, or Spent Caustics, or other regulated substances as defined by the Department shall have an automatic system in place to maintain the Ullage volume of the AST below the Limiting Oxidant Concentration (LOC), for any gaseous Oxidant which may be present, by the use of an Inert Gas Blanketing system in accordance with NFPA 69. Systems operated above the Upper Flammable Limit (UFL) shall be subject to approval by the Department prior to installation. Other methods to prevent a Deflagration such as Spark Extinguishing Systems, Deflagration Suppression, or Deflagration Pressure Containment shall be subject to approval by the Department prior to installation.

12.1.2 The following ASTs shall be exempt from the Inerting requirements of this Section:

12.1.2.1 All existing shop-fabricated ASTs which meet the requirements of UL 142 and the requirements of the Delaware State Fire Prevention Regulations;

12.1.2.2 All existing field-constructed ASTs used for Dispensing which meet the requirements of API 650 and API 2000 and the requirements of the Delaware State Fire Prevention Regulations;

12.1.2.3 New shop-fabricated horizontal ASTs less than or equal to 50,000 gallons and new shop-fabricated vertical ASTs less than or equal to 30,000 gallons used for Bulk Storage which meet the requirements of UL 142 and the requirements of the Delaware State Fire Prevention Regulations;

12.1.2.4 New shop-fabricated horizontal ASTs less than or equal to 50,000 gallons and new shop-fabricated vertical ASTs less than or equal to 30,000 gallons used for Dispensing which meet the requirements of UL 142 and UL 2085 and the requirements of the Delaware State Fire Prevention Regulations;

12.1.2.5 New field-constructed horizontal or vertical ASTs used for Dispensing that meet the requirements of API 650 and API 2000 and the requirements of the Delaware State Fire Prevention Regulations.

12.1.3 An automatic system shall be continuously in place, in use, and operating to designed specifications whenever an AST is in service and has the potential for a flammable atmosphere. The system shall be in place, in use and operated to designed specifications unless the AST has been cleaned sufficiently and purged of flammable vapors to safely permit hot work in, on or around the AST.

12.1.4 An automatic system shall be in place, in use, and operating to designed specifications that continuously monitors the LOC or alternate monitoring parameters as approved by the Department so that whenever the required LOC or alternate monitoring parameters is not met the system shall:

12.1.4.1 Energize an audible and a visual alarm at the location where the operating parameters of the affected AST are monitored and controlled; and

12.1.4.2 Be equipped with an emergency system capable of discontinuing the energy supply to any pumps engaged in moving liquid into or out of the affected AST.

12.1.5 Work to return the system to specified operating parameters shall begin immediately after an alarm is registered. If the AST cannot be returned to the required LOC within 24 hours, the Department shall be notified and be given an indication of when the AST can be returned to the required LOC.

12.1.6 During the time period that the system is not operating within the required LOC no actions shall be taken which unreasonably increase the probability of a deflagration occurring within the affected AST.

12.1.7 The system shall be repaired within a time frame mutually agreed to by the Department and the AST Owner or Operator.

12.1.8 The Department shall be notified within 24 hours when the affected AST is returned to the required LOC.

12.1.9 The gases exhausted or vented from a regulated AST operating under an Inerting system shall be treated in a manner which is compliant with all applicable Department Regulations and Permits.

7 Del. Admin. Code § 1352-B-12.0

20 DE Reg. 815 (4/1/2017)
27 DE Reg. 536 (1/1/2024) (Final)