Extinguisher count from plans: 3 travel distance rules

Key takeaways

• Mark every hazard area on every sheet before you count.
• Measure general areas from the far points, with a unit at 75 feet or less.
• Measure Class B zones from the edge of the hazard area, with a unit at 50 feet or less.
• Measure combustible metal working areas, with a unit or agent container at 75 feet or less.
• Give every floor at least one unit rated not less than 2A.

The method below follows the order you would use on a takeoff. Most of the count comes down to three travel distances. The distance figures and rule wording come from California's regulations in Title 8, which make a good model for how to think about the count. Before you bid, confirm the adopted code for the state and city where the job sits, because other places may set different requirements.

Step 1: Mark the hazard areas on every sheet first

Start with the plans, not the count. Go through every sheet and mark each area where a fire could start or spread. Room names and general notes often tell you more than the walls do. Storage rooms, shops, kitchens, mechanical and electrical rooms, loading docks, and any space where metal is worked deserve their own line on your takeoff sheet, even when they are small.

The regulation does not ask for one number for a whole building. It says that where portable fire extinguishers are provided for employee use, they "shall be selected and distributed based on the classes of anticipated work place fires and on the size and degree of hazard which would affect their use," as stated in California Code of Regulations, Title 8, Section 6151. That sentence is the reason the count has to be done area by area. A large office and a small paint room do not present the same problem, and the sheet should show that difference.

For each marked area, record four things: the floor, the room or zone name, what is stored or done there, and the approximate size. The "what is stored or done" column is the one estimators most often leave blank, and it decides which distance rule applies. If the plans and specifications say nothing about a room's contents, ask the owner or the architect before you guess. A guessed class sends the whole zone down the wrong path, and the error carries through every unit you place in it.

Mark walls, doors, stairs, and elevator lobbies while you are on the sheet too. You will need them in steps two through four when you measure and place units, and it is faster to note them now than to reread every plan later. Mark where any fixed equipment or storage sits, since it can block a route a person would otherwise use to reach a unit. For the field side of this work, see Site walk measures: 3 checks before the takeoff.

Here is a quick example. Suppose a four-floor building has a ground-floor shop, a storage room on the second floor, and open offices on the upper floors. The shop and the storage room each get their own zone line. The offices can share a zone line on each floor, but each floor still gets its own check in step five. By the time you finish this step, the sheet already shows which distance applies to which zone, before you place a single unit.

Step 2: Apply the 75-foot limit to general (Class A) areas

For general-use spaces, the first limit is the one that applies. The quoted rule reads: "The employer shall distribute portable fire extinguishers for use by employees on Class A fires so that the travel distance for employees to any extinguisher is 75 feet (22.9m) or less." The source is California Code of Regulations, Title 8, Section 6151.

Offices, corridors, lobbies, and most other general spaces fall under this rule. Set these spaces aside as the first group on your sheet. Check them against the specification or the owner's fire plan rather than assuming, because a room's contents, not its name, decide the class.

Here is how to run the 75-foot test on the plan:

1. Mark the farthest points in each Class A area. Look for the corners, the far ends of long corridors, and any spot that sits behind a wall, a column, or a partition from the rest of the space.
2. Measure from each far point to the nearest unit along the route a person would walk. If a wall separates a point from a unit and the only way through is a door, measure through the door, not through the wall.
3. If any far point is more than 75 feet from a unit, add one where it closes the gap for the most points, then measure again.
4. Repeat until every marked point in the area is within 75 feet of a unit.

Working from the far corners inward usually finds the gaps faster than starting in the middle of the room. The far corners are the points that set the spacing, so testing them first tells you quickly whether the room needs more units or whether the ones you already placed will do. For the measuring method itself, see takeoff scale setup.

The quoted text does not say whether the 75 feet is measured in a straight line or along a walking path. Read the full section before you settle on a method. If the text still leaves it open, measure along the walking path. That is my recommendation rather than something the quote states, but it is the more conservative choice, and it matches how someone would actually reach a unit in an emergency. A straight-line measurement that passes through a wall is an easy place for a count to go wrong.

Placement matters as much as the measurement. A unit set at a corridor junction or a stair landing, where people already walk, often covers more of the room than a unit hung on blank wall space in a corner. Good placement keeps the count low without failing the test, and it means the unit is where someone will look for it.

Once a unit passes the test, record it on the sheet before you move on. Give each unit an identifier, then write its floor, its zone, the class it serves, and the distance you measured from the farthest point it covers. A unit recorded this way can be checked again in a minute if the plans change. A unit that exists only as a symbol on the drawing usually gets miscounted or double-counted at the end of the job.

Step 3: Apply the 50-foot limit to Class B hazard areas

Class B is the tighter case, and it is easy to get wrong because the starting point changes. The quoted rule reads: "The employer shall distribute portable fire extinguishers for use by employees on Class B fires so that the travel distance from the Class B hazard area to any extinguisher is 50 feet (15.2m) or less." The source is California Code of Regulations, Title 8, Section 6151.

The difference is in the starting point and the number. For Class B, the 50 feet is measured from the hazard area itself, not from wherever an employee happens to stand. And 50 feet is closer than 75 feet, so a Class B zone generally needs units placed more closely together than the general office next door. Do not carry the office spacing into the storage room or the shop, even if the two spaces share a corridor.

Before you count, put the three distances side by side. The table uses only the wording of the quoted rules:

Working a Class B zone follows the same routine as step two, with one change. Draw the edge of each Class B hazard area on the plan, not only its center. Measure outward from that edge to the nearest unit, using the walking route. Any unit that sits within 50 feet of the edge counts toward that zone. If the hazard area is large, check the far side as well. A unit at one end does not prove the other end is covered, so test each part of the boundary that is far from your existing units.

A unit that passes two tests should count once. Mark which zone each unit serves on the sheet. A unit placed for a Class B area that also covers the adjoining hallway should be counted one time, not twice and not dropped. Recording the zone each unit serves also makes the count easy to defend if the plans change and someone asks why a unit is where it is.

Take a storage room on the second floor as an example. Its doorway is the nearest point to the hallway, and its far wall sits about as far from the door as the room is deep. Draw the edge of the room on the sheet, then measure from that edge to the nearest unit in the hall. If the unit is within 50 feet of the edge, the room passes. If it is not, the fix is a second unit inside the room or a unit moved closer to the door, and the choice should be marked on the sheet with the reason, so the bid explains itself.

Illustrative example: a shop in a Class B zone

Assume the far corner of a shop is 60 feet from the nearest unit in the hall. That is past the 50-foot Class B limit, so the zone fails. Add one unit inside the shop about 45 feet from that corner. Every marked point then sits within 50 feet of a unit, and the new unit goes on the sheet with its zone and the distance it covers.

Step 4: Apply the 75-foot limit to combustible metal areas (Class D)

The rule for Class D reads: "The employer shall distribute portable fire extinguishers or other containers of Class D extinguishing agent for use by employees so that the travel distance from the combustible metal working area to any extinguishing agent is 75 feet (22.9m) or less." The source is California Code of Regulations, Title 8, Section 6151.

Two details matter for the count. First, the limit is 75 feet again, but it is measured from the combustible metal working area, not from the employee's position. Second, the rule covers "other containers of Class D extinguishing agent," not only portable extinguishers. That means the takeoff must say what product is specified for the area. Write the product type on the takeoff line so that the count and the bid describe the same item.

Look for these areas on the plans: machine rooms, fabrication bays, and any space described as a metal working area. Measure from the boundary of the working area using the walking-route method from step two. If one space holds both a combustible metal working area and a Class B hazard, it has to pass both tests. Count the units it needs under each rule and then check whether a single unit can serve both, marking it on the sheet only once.

A short practical note: when you price Class D coverage, include the agent containers and any mounting or signage the specification calls for in the same takeoff line. Splitting them across two lines is how a count drifts from the plan.

Step 5: Check every floor against the 2A minimum

Section 1922 of the same Title 8 covers portable firefighting equipment at the job site, and it sets a floor-level minimum: "At least one fire extinguisher rated not less than 2A, shall be provided on each floor." The source is California Code of Regulations, Title 8, Section 1922.

This is a floor minimum, not a substitute for the travel tests. Every floor needs at least one unit rated not less than 2A, and the area tests from steps two through four still apply on top of it. A floor with a single open office can satisfy the floor minimum and still fail the 75-foot test in one far corner. Count the area tests from steps two through four first, then count the floor minimum, and keep the two lists separate on the sheet so you can see which unit covers which requirement.

The same section includes an exception that estimators sometimes read too broadly: "EXCEPTION: Single family residential dwellings other than apartments, lodging houses, hotels or dormitories provided that there is at least one fire extinguisher rated not less than 2A, or the equivalent, available at the job site during working hours." That exception covers single-family residential dwellings. It names apartments, lodging houses, hotels, and dormitories as outside its scope. A commercial or multi-floor job does not fit the exception, so do not reduce the count to one unit for the whole building on that basis.

Walk the floors in order, from the lowest level up:

• Mezzanines, basements, and roof-level equipment rooms are easy to skip on the plans. Give each one its own line so it gets its own check.
• On each floor, write the 2A check first, then list the zones on that floor and the units that serve each zone.
• Where a stair or elevator lobby serves two floors, record which floor each unit is counted under, so the same unit is not claimed twice.

When a floor's area test fails in a far corner, the fix is usually a unit added to that zone, and that unit can sometimes also satisfy the floor minimum. Count it once, under the requirement it satisfies first, and note the other requirement it also meets. This keeps the floor count from being inflated by a unit that was already counted in a zone.

Consider a four-floor building with offices and a shared corridor on each floor. The takeoff then carries four floor minimums, and under each floor sit the zone checks for that floor's offices and corridor. A reviewer can trace every unit back to one floor and one rule, which is what makes the count easy to check. For a related check on counting from plans, see Fall-protection takeoff: 4 items to count from plans.

Step 6: Place units people can see, flag old types, and set the inspection scope

Placement is the last check, and a count that passes on paper can still fail in the building if the units are hard to find. The Washington rule states: "(c) All firefighting equipment, provided by the employer, must be conspicuously located." The source is Washington State Legislature, WAC 296-155-260. That is Washington's rule, not California's, so check your own state's requirements. The practical point still holds: a unit that a worker cannot find quickly does not serve the count you just made.

On the sheet, note whether each unit is visible from the route people walk. Avoid placing a unit behind stored material, inside a closet, or where equipment blocks the view. Read the placement notes in the specification for signage or mounting requirements, and carry those into the bid as part of the same takeoff line.

Older buildings need one more check. California's rule requires employers to permanently remove from service, by January 1, 1982, soldered or riveted self-generating soda acid or self-generating foam or gas cartridge water type portable fire extinguishers that are operated by inverting the extinguisher to rupture the cartridge or to initiate an uncontrollable pressure generating chemical reaction to expel the agent. The source is California Code of Regulations, Title 8, Section 6151. If a walk-through of an older building turns up a unit of that type, do not count it toward the requirement. Add its replacement to the scope instead.

Finally, the count sets the inspection scope. The rule states: "The employer shall be responsible for the inspection, maintenance and testing of all portable fire extinguishers in the workplace." The source is California Code of Regulations, Title 8, Section 6151. Your bid should say who carries that duty and list the units by floor, so the inspection scope matches the count exactly.

Plans change during bidding and construction, and a count that was right last week may not be right now. When a wall moves, a room changes use, or a shop is added, rerun the tests only for the zones that the change touches, and note the revision on the sheet with its date. Re-measuring the whole building for one small change wastes time, while leaving an old count in place can put a gap into the bid.

Before you send the count, run one last pass. Confirm that each unit appears once, with its floor, zone, class served, and the rule that set its location. Confirm that every floor has its 2A minimum. Confirm that every marked point in a Class A, Class B, or Class D area is within its distance limit. Then check that the total on the sheet matches the total in the bid.

Three travel distances drive the count: 75 feet for general areas, 50 feet from Class B hazard areas, and 75 feet from combustible metal working areas. The floor minimum and the placement check then finish the job. Run each area against its own rule, keep the lists separate, and the count will hold up when the plans change.

Your next step

Today, pick one floor on the plans, mark its hazard areas, and run the 75-foot test on its general spaces before you open any other sheet.

Related guides: Buried utility takeoff: three limits before bids · Convert takeoff units in 3 steps using conversion factors.

Frequently asked questions

How far can an extinguisher be from people in a general office?

Under the quoted Class A rule, the travel distance to any extinguisher must be 75 feet or less.

Does a multi-floor building need only one extinguisher?

No. Each floor needs at least one unit rated not less than 2A, and the area tests still apply on top of that minimum.