17C.60.160 Fire Flow Requirements

A. Scope. This Section addresses fire flow requirements for all buildings, portions of buildings, and facilities hereafter constructed. The requirements of this Section shall supersede any conditions, notes, or requirements on any plat when the Fire Marshal finds it creates a serious threat to the public health, safety, or welfare. Nothing in this Section shall be deemed to reduce, replace or waive any water system requirements in PCC 17C.60.165 or any other Pierce County Code.

1. Water mains supplying fire flow shall maintain a minimum residual pressure of not less than 20 pounds per square inch (PSI) automatically.

2. A Certificate of Water Availability and water system vicinity map that is signed by the water purveyor shall be submitted at the time of building permit application for all newly constructed or modified buildings located within a water district.

3. The fire-flow calculation area shall be the total floor area of all floor levels within the exterior walls and under the combustible horizontal projections of the roof of a building with consideration to the following:

a. Buildings with Type IA and IB construction shall use the area of the three largest successive floors.

b. Open parking garages shall be determined by the area of the largest floor.

c. Any building constructed in the IRC located within 10 feet of another building on the same lot shall be considered as one fire flow calculation area unless separated by a fire-rated assembly.

d. Any building constructed in the IBC located within 20 feet of another building on the same lot shall be considered as one fire flow calculation area unless separated by a fire-rated assembly.

e. Each portion of a building separated by one or more fire-rated assemblies are considered as separate fire flow calculation areas.

f. Fire-rated assemblies are not permitted to reduce the fire flow calculation area within single-family residential dwellings.

Exception. Fire-rated assemblies are permitted to "separate" an attached garage from a residence and reduce by compartmentalization, the fire area of accessory buildings.

C. Fire Flow Requirements for Facilities. Facilities shall be provided with a minimum of 1,500 GPM for two hours. The requirement may be modified by the Fire Marshal per the International Fire Code, Appendix B.103.

D. Fire Flow Requirements for Buildings. Fire flow shall be automatically available and supplied at a residual pressure of not less than 20 PSI.

a. Dwellings and Accessory Structures with Habitable Space. The fire flow requirements for dwellings and accessory structures with habitable space shall be as follows:

(1) Fire flow calculation area of less than 3,600 square feet shall be 750 GPM for 45 minutes;

(2) Fire flow calculation area of 3,600 square feet or more shall be 1,000 GPM for one hour.

(3) For replacement of manufactured and mobile homes in a park, fire flow is not required if all of the following are met:

(a) The home has a Class A or B roof; and

(b) Has a 10-foot clearance between the home and any adjacent home.

(1) The fire flow requirements for accessory structures greater than 3,600 square feet shall be 750 GPM for 45 minutes.

(2) Exceptions to fire flow requirements:

(a) Buildings set back from all side and rear property lines of at least 20 feet and a minimum of 30 feet from other buildings on the same lot.

(1) The fire flow requirements for agricultural buildings greater than 3,600 square feet (Group U) shall be 750 GPM for 45 minutes;

(2) Exception to fire flow requirements:

(a) The structure is set back from the side and rear lot lines of at least 30 feet and is at least 30 feet from other buildings on the same lot.

2. Buildings Constructed in the International Building Code and All Townhomes and Accessory Structures 3,600 Square Feet or Greater. The fire flow and duration requirements shall be as specified in Table 17C.60-3. Reductions to the required fire flow are permitted for an approved fire sprinkler system as follows:

(1) Installation of an NFPA 13 fire sprinkler system reduces the fire flow requirement by 75 percent, except for H occupancies which are reduced by 50 percent.

(2) Installation of an NFPA 13R fire sprinkler system reduces the fire flow requirement by 50 percent.

(3) Installation of an NFPA 13D fire sprinkler system reduces the fire flow requirement by 25 percent.

E. Exceptions to Fire Flow. The following exceptions apply to fire flow requirements for new buildings:

1. Fire protection credits as described in Table 17C.60-5 may be used in lieu of providing fire flow.

2. When at least 750 GPM for a duration of 45 minutes is available from an approved fire hydrant, it shall be credited toward the required fire flow. The additional fire flow requirement may be provided by using fire protection credits as described in Table 17C.60-5.

1. Buildings that are 600 square feet or less, located a minimum of 10 feet from property lines and 20 feet from structures, and not classified as Occupancy Group R, H, or I.

2. Storage structures that are used for the sole purpose of storing mineral products such as salt, sand, and/or rock, for road maintenance, or similar purposes that meet all of the following criteria:

a. Parking of motor vehicles in the storage shed shall be prohibited.

b. The storage of flammable or combustible materials in the storage shed shall be prohibited.

c. The roof covering shall be of Class A or B fire-resistant roofing material or meet NFPA 701.

d. Located a minimum of 20 feet from other structures.

3. Play sheds associated with schools and/or churches that meet all of the following criteria:

a. Do not require an automatic sprinkler system based on International Building Code requirements.

b. There shall be no restrictions to egress, i.e., benches, rails, walls, etc.

c. There shall be no interior walls or partitions within the roof line.

d. The roof covering shall be of Class A or B fire-resistant roofing material.

e. Located a minimum of 20 feet from other structures.

4. Picnic shelters that are 2,500 square feet or less and meet all of the following criteria:

a. Do not require an automatic sprinkler system based on International Building Code requirements.

b. All cooking within the picnic shelter shall be done within approved devices provided for that purpose.

c. There shall be no open burning within a picnic shelter except within an approved appliance or fireplace provided for that purpose.

d. There shall be a minimum of one exit on each side of the picnic shelter.

e. The roof covering shall be of Class A or B fire-resistant roofing material.

f. Located a minimum of 20 feet from other structures.

5. Vehicle covers/carports that meet all of the following criteria:

a. The vehicle cover shall be associated with a residential use.

b. The vehicle cover shall be located a minimum of three feet from property lines.

c. The vehicle cover shall be open on three sides.

6. Commercial buildings less than 3,600 square feet that meet all of the following criteria:

a. The fire area building is less than 3,600 square feet.

b. The property is located in a rural zone.

c. An NFPA 72 monitored fire alarm is installed in the building.

d. Thirty-foot minimum setbacks to all property lines and buildings on the same property.

e. Located within a fire district.

f. Not classified as an E, A, H, I, or R occupancy.

G. Hydrants. These standards shall apply to all new hydrant installations and when existing hydrants are replaced.

1. The location of hydrants shall be determined by the Fire Marshal, guided by the following:

a. The average spacing between fire hydrants for construction using the IBC and all townhomes shall not exceed that listed on Table 17C.60-4. Regardless of the average hydrant spacing, no portion of a building shall be farther from a hydrant than that distance listed in the last (far right) column of Table 17C.60-4. Distances shall be measured along approved EV Accesses and adjacent public and private roads and shared access facilities.

b. For residential buildings, the distance from the center point of lot frontage to a hydrant shall not exceed 350 feet, except as provided for in subsection G.1.c below.

c. Hydrants are not required on dead-end streets or shared access facilities not exceeding 600 feet in length and serving only residential buildings if there is an approved hydrant at the intersection.

d. Hydrants shall be provided along approved EV Accesses and adjacent public and private roads and shared access facilities. When practical, hydrants shall be located at street intersections. See Table 17C.60-4.

e. All new and existing approved public hydrants shall be considered available if accessible to the fire department by public or private roads, or shared access facilities, or approved on-site EV Accesses.

2. Exceptions to Hydrant Requirements. When hydrants cannot be installed in conformance with these standards due to topography, non-negotiable grades, or other similar conditions, the Fire Marshal may confer with the local Fire Chief, and may allow exceptions to these standards by requiring additional fire protection as specified in the most current edition of the International Fire Code adopted by the County.

3. Hydrant Valve Openings. Standard hydrants shall have not less than 5-inch main valve openings (MVO) with two 2 1/2 inch National Hose (N.H.) outlet ports and one 4 1/2 inch N.H. outlet port. All 4 1/2 inch outlet ports shall have 5-inch storz fittings. Hydrants shall meet current American Water Works Association (A.W.W.A.) Standards.

4. System Design for Automatic Operation. Water distribution systems supplying water for fire flow to fire hydrants shall be designed to maintain the designed and/or required water volume automatically.

TABLE 17C.60-3
Required Fire Flow for All Buildings Constructed Using the International Building Code, All Townhomes, and Accessory Structures Over 5,000 Square Feet
		Construction Type in Accordance with the IBC
DURATION (HOURS)	REQUIRED FIRE FLOW (GPM)	IA and IB	IIA and IIIA	IV-H.T. VA	IIB IIIB	VB
DURATION (HOURS)	REQUIRED FIRE FLOW (GPM)	WHEN TOTAL FIRE FLOW CALCULATION AREA IN SQUARE FEET IS EQUAL TO OR LESS THAN THESE VALUES
2	1,500	500	500	500	500	500
2	1,500	5,500	3,700	2,600	2,100	1,600
2	1,500	11,100	6,800	4,700	3,500	2,400
2	1,500	15,900	9,300	6,200	4,500	2,900
2	1,500	22,700	12,700	8,200	5,900	3,600
2	1,750	30,200	17,000	10,900	7,900	4,800
2	2,000	38,700	21,800	12,900	9,800	6,200
2	2,250	48,300	24,200	17,400	12,600	7,700
2	2,500	59,000	33,200	21,300	15,400	9,400
2	2,750	70,900	39,700	25,500	18,400	11,300
3	3,000	83,700	47,100	30,100	21,800	13,400
3	3,250	97,700	54,900	35,200	25,900	15,600
3	3,500	112,700	63,400	40,600	29,300	18,000
3	3,750	128,700	72,400	46,400	33,500	20,600
4	4,000	145,900	82,100	52,500	37,900	23,300
4	4,250	164,200	92,400	59,100	42,700	26,300
4	4,500	184,400	103,100	66,000	47,700	29,300
4	4,750	203,700	114,600	73,300	53,000	32,600
4	5,000	225,200	126,700	81,100	58,600	36,000
4	5,250	247,700	139,400	89,200	65,400	39,600
4	5,500	271,200	152,600	97,700	70,600	43,400
4	5,750	295,900	166,500	106,500	77,000	47,400
4	6,000	GREATER	GREATER	115,800	83,700	51,500
4	6,250			125,500	90,600	55,700
4	6,500			135,500	97,900	60,200
4	6,750			145,800	106,800	64,800
4	7,000			156,700	113,200	69,600
4	7,250			167,900	121,300	74,600
4	7,500			179,400	129,600	79,800
4	7,750			191,400	138,300	85,100
4	8,000			GREATER	GREATER	GREATER

TABLE 17C.60-4
Number and Distribution of Hydrants
Minimum Fire Flow Requirement (GPM)	Minimum # Of Hydrants	Average Spacing Between Hydrants (FT (1))	Maximum Distance From Hydrant to Any Portion of Building (FT)

500 – 1250	1	700	350
1500 – 1750	2	500	250
2000 – 2250	2	450	225
2500 – 2750	3	450	225
3000 – 3250	3	400	225
3500 – 4250	4	350	210
4500 – 5250	5	300	180
5500 – 5750	6	300	180
6000 – 6250	6	250	150
6500 – 7250	7	250	150
7500 or more	8 or more (2)	200	120
(1) Where streets are provided with median dividers or where arterial streets are provided with four or more traffic lanes and have a traffic count of more than 30,000 vehicles per day, hydrant spacing shall comply with Table 17C.60-8 on both sides of the street. (2) One hydrant for each 1000 GPM or fraction thereof.

TABLE 17C.60-5
Residential Fire Protection Credits
Options to Reduce Fire Flow (1)	% of Reduction
NFPA 13 D sprinkler system (Required for structures 5,000 sq. ft. and greater)	100%
Building less than 2,000 sq. ft. or	-45%
Building less than 3,600 sq. ft.	-25%
Building less than 3,600 sq. ft. and minimum 50' setbacks to side and rear property lines	-5%
Accessory or Agricultural Structure Less than 3,600 sq. ft. without habitable space	-40%
Accessory or Agricultural Structure less than 3,600 sq. ft. without walls	-35%
30' setback to sides and rear property lines or	-20%
20' setback to sides and rear property lines	-15%
Fire-Rated Wallboard Throughout Interior	-20%
Class A or B roof Metal Roof	-20% 30%
Exterior Siding Materials with a Class A or B Fire Rating	30%
Approved Kitchen Hood Suppression System	-25%
Monitored Residential Fire Alarm System	-25%
Existing Hydrant Credits:
Structures less than 3,600 sq. ft.
750 GPM/45 Min. Located 0-350'	100%
750 GPM/45 Min. Located 351'-500'	75%
Structures 3,600 sq. ft or Greater
1,000 GPM/60 Min. Located 0-350'	100%
750 GPM/45 Min. Located 0-350'	75%
1,000 GPM/60 Min. Located 351'-500'	75%
750 GPM/45 Min. Located 351'-500'	50%
Fire hydrants used for fire flow credits must be on the same side of the street that the building is on.