About this chapter: Chapter 21 provides provisions that are intended to reduce hazards associated with use of flammable and combustible dry cleaning solvents. These materials, like all volatile organic chemicals, generate significant quantities of static electricity and are thus readily ignitable. Many flammable and nonflammable dry cleaning solvents also possess health hazards when involved in a fire.
- Class I solvents are liquids having a flash point below 100°F (38°C).
- Class II solvents are liquids having a flash point at or above 100°F (38°C) and below 140°F (60°C).
- Class IIIA solvents are liquids having a flash point at or above 140°F (60°C) and below 200°F (93°C).
- Class IIIB solvents are liquids having a flash point at or above 200°F (93°C).
- Class IV solvents are liquids classified as nonflammable.
- Type I—systems using Class I solvents.
- Type II—systems using Class II solvents.
- Type III-A—systems using Class IIIA solvents.
- Type III-B—systems using Class IIIB solvents.
- Type IV—systems using Class IV solvents in which dry cleaning is not conducted by the public.
- Type V—systems using Class IV solvents in which dry cleaning is conducted by the public.
Type IV and V dry cleaning systems shall be provided with an automatically activated exhaust ventilation system to maintain an air velocity of not less than 100 feet per minute (0.51 m/s) through the loading door when the door is opened. Such systems for dry cleaning equipment shall comply with the International Mechanical Code.
Exception: Dry cleaning units are not required to be provided with exhaust ventilation where an exhaust hood is installed immediately outside of and above the loading door and operates at an airflow rate as follows:
Q= flow rate exhausted through the hood, cubic feet per minute (m3/s).
ALD = area of the loading door, square feet (m2).
Where approved, articles that cannot be washed in the usual washing machines are allowed to be cleaned in scrubbing tubs. Scrubbing tubs shall comply with the following:
- Only Class II or III liquids shall be used.
- The total amount of solvent used in such open containers shall not exceed 3 gallons (11 L).
- Scrubbing tubs shall be secured to the floor.
- Scrubbing tubs shall be provided with permanent 11/2-inch (38 mm) drains. Such drain shall be provided with a trap and shall be connected to an approved container.
- 1.1. Prevent oxygen concentrations from reaching 8 percent or more by volume.
- 1.2. Keep the temperature of the solvent not less than 30°F (16.7°C) below the flash point.
- 1.3. Maintain the solvent vapor concentration at a level lower than 25 percent of the lower explosive limit (LEL).
- 1.4. Utilize equipment approved for use in Class I, Division 2 hazardous locations in accordance with NFPA 70.
- 1.5. Utilize an integrated dry-chemical, clean agent or water-mist automatic fire-extinguishing system designed in accordance with Chapter 9.
- An automatic sprinkler system shall not be required in Type III-B dry cleaning plants where the aggregate quantity of Class III-B solvent in dry cleaning machines and storage does not exceed 3,300 gallons (12 490 L).
Type II dry cleaning units, washer-extractors, and drying tumblers in Type II dry cleaning plants shall be provided with an approved automatic fire-extinguishing system installed and maintained in accordance with Chapter 9.
Exception: Where approved, a manual steam jet not less than 3/4 inch (19 mm) with a continuously available steam supply at a pressure not less than 15 pounds per square inch gauge (psig) (103 kPa) is allowed to be substituted for the automatic fire-extinguishing system.