The number of fire extinguishers required on a job site depends on several factors, including the size of the protected area, the type of potential fire hazards, and the amount of flammable or combustible liquids present 1, 2.

Here's a breakdown of the requirements:

• General Requirements: At least one fire extinguisher with a rating of not less than 2A must be provided for each 3,000 square feet of protected building area [1]. The travel distance from any point in the protected area to the nearest fire extinguisher should not exceed 100 feet [1].
• Multistory Buildings: In multistory buildings, at least one fire extinguisher should be located adjacent to the stairway [2].
• Flammable Liquids: A fire extinguisher with a rating of not less than 10B must be provided within 50 feet of any location where more than 5 gallons of flammable or combustible liquids or 5 pounds of flammable gas are being used on the job site [2]. This requirement does not apply to the integral fuel tanks of motor vehicles [2].
• Alternative Options:
  • One 55-gallon open drum of water with two fire pails may be substituted for a fire extinguisher having a 2A rating [2].
  • A 1/2-inch diameter garden-type hose line, not to exceed 100 feet in length and equipped with a nozzle, may be substituted for a 2A-rated fire extinguisher, provided it can discharge a minimum of 5 gallons per minute with a minimum hose stream range of 30 feet horizontally [2]. The hose lines should be mounted on conventional racks or reels, with enough racks or reels to ensure that at least one hose stream can reach all points in the area [2].
• Specific Hazards: Portable fire extinguishers should be placed not more than 9 meters away from each industrial open-flame portable heating device, tar pot, or asphalt kettle in use, and each welding or cutting operation in progress [3].

It is also important to consider the following:

• The employer is responsible for developing a fire protection program that includes providing the necessary firefighting equipment [1].
• All firefighting equipment must be conspicuously located and maintained in operating condition [1].
• Access to all firefighting equipment must be maintained at all times [1].
• Fire extinguishers and water drums that are subject to freezing must be protected from freezing [2].
• Portable fire extinguishers should be selected, located, inspected, maintained, and tested to protect the health and safety of workers [3].

Always refer to the specific regulations and guidelines applicable to your location and type of work to ensure full compliance.