Division B
Acceptable Solutions

Part 4 — Flammable and Combustible Liquids

Section 4.9. Process Plants

4.9.1. Scope

4.9.1.1. Application

1) Except as provided in Sentence (2), this Section applies to process plants, including refineries, that contain industrial processes involving flammable liquids or combustible liquids.I

2) This Section does not apply to distilleries covered in Section 4.10.I

4.9.2. Outdoor Processing Equipment

4.9.2.1. Location

1) The location of outdoor processing equipment in process plants shall be based on its flammable liquid or combustible liquid capacity as described in Sentences (2) to (4).I

2) Except as provided in Sentence (4), outdoor processing equipment having emergency relief venting and a working pressure of not more than 17 kPa (gauge) shall be separated from property lines and buildings on the same property by distancesI

a)equal to those in Table 4.3.2.1. for stable liquids, and

b)2.5 times those in Table 4.3.2.1. for unstable liquids.

3) Except as provided in Sentence (4), outdoor processing equipment having emergency relief venting and a working pressure more than 17 kPa (gauge) shall be separated from property lines and buildings on the same property by distancesI

a)1.5 times those in Table 4.3.2.1. for stable liquids, and

b)4 times those in Table 4.3.2.1. for unstable liquids.

4) Where protection is not provided against fires or explosions in processing equipment, the distances in Sentences (2) and (3) shall be doubled. (See Sentence 4.3.2.5.(2).) I

4.9.3. Processing Buildings

4.9.3.1. Explosion Venting

1) Except as provided in Article 4.9.4.2., where Class IA liquids or unstable liquids are processed within a room or a building, the room or building shall be designed to prevent critical structural and mechanical damage from an internal explosion in conformance with good engineering practice such as that described in NFPA 68, “Venting of Deflagrations.” (See A-3.2.8.2.(1)(d) in Appendix A.)I

4.9.3.2. Fire Separations

1) Areas where unstable liquids are handled or where small scale unit chemical processes are carried on shall be separated from the remainder of the building by a fire separation having a fire-resistance rating of not less than 2 h.I

4.9.3.3. Basements and Pits

1) Buildings where Class I and II liquids are handled in chemical processes shall not have basements or covered pits.I

4.9.3.4. Ventilation

1) Equipment used in a building and the ventilation of the building shall be designed so as to limit flammable vapour-air mixtures under normal operating conditions to the interior of equipment, and to not more than 1.5 m from such equipment. (See Appendix A.)I

4.9.4. Fire Prevention and Protection

4.9.4.1. Spill and Vapour Control

1) Processing equipment shall be designed and arranged toI

a)prevent the unintentional escape of liquids and vapours, and

b)minimize the quantity escaping in the event of accidental release.

4.9.4.2. Explosion Protection

1) Processing equipment where an explosion hazard is present shall beI

a)designed to withstand the explosion pressure without damage to the equipment,

b)provided with explosion venting in conformance with NFPA 68, “Venting of Deflagrations,” or

c)provided with an explosion prevention system in conformance with NFPA 69, “Explosion Prevention Systems.”

4.9.4.3. Fire Protection

1) Where the process warrants such protection, industrial process plants shall be supplied withI

a)water supplies of adequate pressure and quantity to meet the probable fire demands,

b)hydrants,

c)hoses connected to a permanent water supply and located so that all equipment containing flammable liquids or combustible liquids, including pumps, can be reached with at least one hose stream,

d)nozzles capable of discharging a water spray, and

e)automatic fire suppression systems.

4.9.4.4. Emergency Procedures

1) Emergency procedures conforming to Article 4.1.5.5. shall be established for refineries and process plants.I