Rules for Flammable Liquids in Industrial Plants
| Good housekeeping is an absolute requirement when there are hazardous materials in your work. Most industrial plants have some kind of flammable liquids on site. And since the primary hazards are explosion and fire, the consequences of improper storage and handling can be disastrous. |
Flammable liquids are divided into four categories as follows:
- Category 1 includes liquids having flashpoints below 73.4°F (23°C) and having a boiling point at or below 95°F (35°C).
- Category 2 includes liquids having flashpoints below 73.4°F (23°C) and having a boiling point above 95°F (35°C).
- Category 3 includes liquids having flashpoints at or above 73.4°F (23°C) and at or below 140°F (60°C). When a Category 3 liquid with a flashpoint at or above 100°F (37.8°C) is heated for use to within 30°F (16.7°C) of its flashpoint, it must be handled in accordance with the requirements for a Category 3 liquid with a flashpoint below 100°F (37.8°C).
- Category 4 includes liquids having flashpoints above 140°F (60°C) and at or below 199.4°F (93°C). When a Category 4 flammable liquid is heated for use to within 30°F (16.7°C) of its flashpoint, it must be handled in accordance with the requirements for a Category 3 liquid with a flashpoint at or above 100°F (37.8°C).
Flammable Liquids in Industrial Plants
Rules for flammable liquids in industrial plants are found at 29 CFR 1910.106(e). Here's a quick review.Incidental storage or use of flammable liquids. All storage must be in tanks or closed containers. The quantity of liquids allowed in manufacturing/production areas (outside of primary storage) is limited according to the liquid category and whether a container or a tank is utilized for storage. Transfer of liquids must be separated from other operations by adequate distance or fire-resistant construction. A closed piping system, safety cans, or a gravity system may be used for transfer. Air pressure transfer is prohibited. Adequate ventilation must be maintained. Means of spill or leakage prevention, control, cleanup, and disposal must be provided. Any possible source of ignition must be eliminated when using Category 1 liquids.
Unit-physical operations. Physical operations are restricted to operations not involving chemical change. All buildings and equipment must be accessible for fire-fighting purposes. Unstable liquids and small-scale chemical processes must be isolated by a 2-hour (minimum) firewall. Emergency drainage systems must direct flammable liquids to a safe location. Appropriate ventilation must be maintained when using Category 1 liquids so as to provide adequate air exchange, discharge to a safe location, and proper ventilation of floor areas or pits. Equipment must be of appropriate design for use with Category 1 liquids so as to limit flammable vapor-air mixtures.
Tank vehicle and tank car loading and unloading. The distance of separation from aboveground tanks, warehouses, other plant buildings, or nearest adjoining property lines is based on liquid category. Fire control. Fire control equipment, water supply, and any special extinguishing equipment must be adequately maintained and periodically inspected and be appropriate in quantity and type for the potential hazards. Local fire marshals must be consulted to determine specific requirements.
Fire control. Fire control equipment, water supply, and any special extinguishing equipment must be adequately maintained and periodically inspected and be appropriate in quantity and type for the potential hazards. Local fire marshals must be consulted to determine specific requirements.
Sources of ignition. Possible sources of ignition must be carefully identified and controlled. Dispensing of Category 1 liquids must be done with proper grounding.
Electrical. Locations (including surrounding areas) where flammable vapor-air mixtures may exist under normal conditions must meet Class I, Division 1 standards. Locations (including surrounding areas) where flammable vapor-air mixtures may exist under abnormal conditions must meet Division 2 standards. If only Category 3 and 4 liquids are used, ordinary electrical equipment is permitted.
Maintenance and repair. Maintenance and repair, including hot work, are permitted only under the supervision of a responsible individual in charge. This individual must make an inspection of the area before and after work.
Housekeeping. Housekeeping must be adequate to control leaks and prevent spills. Aisle space must be adequate for fire response access. Combustible wastes and residues must be minimized, stored properly, and disposed of daily. Ground area around buildings and unit operating areas must be kept free of weeds, trash, or other unnecessary combustible materials.