First Nations (Alberta) Technical Services Advisory Group

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Fire ProgramHydrant Flows & CalculationsWater supply

Types of Water Supply

Water distribution systems

Types of Hydrants

National Building Code of Canada 2005

Hydrant calculations and flows

Hydrant color codes

Questions

Water Supply

1 of the most critical elements of fighting a fire and w/o it, its not even a fight.

Fire trucks, hoses, and appliances are useless.

Where it comes from and how much is available are key questions we ask

ourselves

Water supply cont..

Water supply dictates the Fire Flow Capacity

Pressure, is the force, or weight (kgs or lbs) of water measured over an area

(sq.cm or sq.in)

The Fire Flow Requirement is the amount of water required for putting out the fire.

Water Supply cont..

Knowing the amount of water available and how much is needed lets fire fighters

select the right strategy, tactics, hose

appliances and fire streams.

All are interrelated; a large fire without sufficient water leads to failure, and

property and possible lives will be lost as a

result.

Types of Water Supply

Ground Water-Aquifers

Surface Water

Mobile Water Supply Apparatus

Water Distribution Systems

Water is supplied in 3 ways.

1) Gravity fed, the water source is at a

higher elevation

2) The next is a pumped system

3) And a combination gravity-pumped

system

Water distribution cont..

Types of Hydrants

Wet Barrel, have water in the barrel up to

the valves of each port. These are used in

areas not subject to freezing

temperatures; primarily in California and

Florida.

California Hydrant

California Hydrant design

Types of Hydrants

Dry Barrel, are used in areas where freezing

temperatures could damage the hydrant. It

uses a valve at the base of the hydrant to

control water flow to all outlets.

When the dry barrel hydrant valve is closed

or partially open, a drain allows the water

to drain from the hydrant preventing

damage from freezing.

Dry Barrel Hydrant

Dry Barrel design

Types of hydrants

Dry Hydrant, is not really a hydrant but a

connection point for Drafting from a static

water source such as a pond or a stream.

Dry Hydrant

Dry Hydrant design

NBC 2005 Water Supply

Part 3

Fire Protection, Occupant Safety and Accessibility

Division B 3.2.5.7 Water Supply

1) Every building shall be provided with an adequate water supply for fire fighting.

(See Appendix A.)

A-3.2.5.7.(1) Water Supply

The intent of this sentence is that an adequate water supply for fire fighting be

readily available and of sufficient volume

and pressure to enable emergency

response personnel to control fire growth

so as to enable safe evacuation of

occupants and the conduct of search &

rescue operations, prevent the fire from

spreading to adjacent buildings, and

provide a limited measure of property

protection.

A-3.2.5.7.(1) Water Supply

cont..

The volume of on-site water supply is dependent on the building size,

construction, occupancy, exposure, and

environmental impact potential, and

should be sufficient to allow at least 30

minutes of fire department hose stream

use.

Quick calculation!

Typical triple combination pumper found on First Nation fire dept.

4000 lpm pump X 30 min = 120,000 litres

Convert to gallons X 0.2642 = 31,704 gallons in 30 minutes.

Calculation cont

I wonder if wed have enough capacity to pump that much water and what if it takes

longer to extinguish?

Hydrant Calculations & Flows

Flow tests on hydrants

The most accurate test is made using 2 hydrants. A gauge is attached to an outlet;

this gauge shows normal operating

pressure on the hydrant and main with no

water flowing. i.e. flushing the toilet,

washer, etc.

Flow tests on hydrants cont..

Then when water is discharged from another hydrant this gauge will then show

the residual or pressure left in the main.

From pressures read at the two hydrants, the fire flow available at any residual can

be calculated.

Flow tests on hydrants cont..

Flow tests cont..

Attach static gauge and turn on hydrant and we may get a reading of 50 psi.

Attach flow meter or pitot gauge and flow water at the other hydrant, take reading of

flow.

As the other hydrant flows take another static reading and measure the drop in

pressure.

Flow test cont..

Note*

It is important that Residual Pressure should never drop below 140 kpa or (20

psi)

Flow test contcoefficients

Flow test cont. Formula used:

Q = 0.067 x c x d of x FP

Q = where Q is quantity in gallons,

C is the coefficient of the outlet in

millimeters squared

And FP is the square root of pressure in kpa

Flow test cont

Q = 0.067 x 0.9 x 65 x 350

Q = 0.067 x 0.9 x 4225 x 18.71

= 4767 lpm

Flow test cont

Recent flow test examples:

0.067 x 0.9 x 4225 x 11.84 or (20psi)

= 3017 lpm

0.067 x 0.9 x 4225 x 3.16 or (10 psi)

= 805 lpm

Color Codes for hydrants

Any Questions?