Water Supplies

Question 1

Name & describe 2 major water sources.

Answer 1

Static supplies These are bodies of water that can be tapped into. This includes pools, dams, rivers, lakes etc. Reticulated supplies These are systems of water i.e. Contained network of pipes (mains). These are accessed via hydrants

Question 2

Describe flow and pressure and provide 3 examples of what can affect each

Answer 2

Flow - quantity of water at a given time Flow is affected by; - Diameter of main - the condition if the internal surface of the main e.g. corrosion or tuberculation which affects smoothness- Pressure the main is workingPressure - Force at which water is delivered. It pushes water through the lines and equipment.Force is affected by; - the length of the main between the pipe or other pressure source such as reservoir and the hydrant - How many people are using it (quantity) - How many and size of hoses or appliances attached to the main - whether there are pumping stations/boosters in the system

Question 3

Name and describe 3 hydrant types

Answer 3

1. Spring valve hydrant (ball valve) - Main type of hydrant used today - Standpipe fits into the ground and as you turn the hand wheel the ball is pushed down to allow for water flow. - Located in hydrant pits marked with FH2. High capacity hydrant - Can supply larger volumes of water - Located near high risk areas 3. Pillar hydrants - They have a hand wheel on top - Some are not connected to water supply anymore but are heritage listed

Question 4

what would you find in a Hydrant booster?

Answer 4

As a general rule, any building with 2 or more floors in either direction will have an external hydrant system - connection points that allow ff to connect to the hydrant to boost pressure- 2 lines in 2 lines out - usually twin 65 Storz with a pressure gauge above stating operating pressure- access to mains supply- block plan- sign with maximum test and operating pressures

Question 5

Where might you expect to find a booster hydrant in a pre 1994 building and a post 1994 building?

Answer 5

Pre 1994 - located no more than 4m from an exit Post 1994 - located inside a fire isolated stair well

Question 6

Purpose of Standpipe? how do you ship a standpipe?

Answer 6

Allows for access to the water inside of a hydrant To ship a standpipe you must; - before and after use, check the condition of the washer (o-ring) on the base of the standpipe - ensure the flange is connected firmly underneath the bayonet lugs on the ball valve hydrant- Place standpipe into hydrant and rotate until the lugs are under the bayonet lugs - Rotate in clockwise direction until secure - While bracing the top of the standpipe, turn the hand wheel keeping your head so it is not directly above the standpipe - Flush the water from the hydrant until it is clear.

Question 7

Name and describe the 3 Mains

Answer 7

A main is an access point to a reticulated supply of water 1. Trunk main - 600mm to 3000mm- Delivers water from source to treatment plants then onto reservoirs 2. Service mains - 100mm residential areas - 150-600mm in industrial areas- laid underground, consumers draw their water from them by smaller pipes - Hydrants often placed alongside the road approx. 90m apart 3. Ring mains - High risk/priority areas e.g. schools, hospitals, fuel depots- water travels both ways around the loop.- if one loop impacted, water still available on the other loop- shut off valves can also be fitted

Question 8

What is water hammer and how can it be prevented

Answer 8

• Occurs when water flow is suddenly shut off. - The pressure of water must then be absorbed by the pipes and fittings - This can rupture hose joints, hydrants, water mains or pump casings To avoid water hammer:- shut off branches smoothly and steadily- shut off hydrants smoothly and steadily- shut off deliveries and collectors at the pump smoothly and steadily- If driving over a hose that is charged it should be done slowly

Question 9

Hydrant locations

Answer 9

• generally indicated with by a ‘FH’, on the kerb, a power pole, fence or headstone marker- on the road and adjacent to it a blue ‘cats-eye’ - Positioned 60-90m apart - cul de sacs - at the end or either side of the entrance- Large shopping centres will have a high capacity hydrant at 135m intervals with standard ones at 45m intervals - One standard hydrant at 180m intervals on roads where no fire risk other than vehicle fires- MDTs also have capcity to assist in locating hydrants (blue dots). Mirrorred of CAD that Comcen also use.