US 30605

US 30605

Install, secure, and maintain water supply pipework in buildings

_{Images & videos courtesy youtube.com & google.com}

Reference documents

•NZBC G12 Water Supplies / G1

•AS/NZS 3500.1 Water services

Standards

A clean water supply, is the single most important determinant of public health

• In the mid-19th century, the Soho district of London had a serious problem with filth due to the large influx of people and a lack of proper sanitary services: Many cellars (basements) had cesspools of night soil underneath their floorboards. Since the cesspools were overrunning, the London government decided to dump the waste into the River Thames. This action contaminated the water supply, leading to the cholera outbreak.

Outbreak

• On 31 August 1854, after several other outbreaks had occurred elsewhere in the city, a major outbreak of cholera struck Soho. John Snow, the physician who eventually linked the outbreak to contaminated water, later called it "the most terrible outbreak of cholera which ever occurred in this kingdom."

  
  

• Cholera is a fast-developing, highly contagious infection that causes diarrhea, leading to severe dehydration and possible death

Water bourn disease

• Cholera is an infection of the small intestine caused by the bacterium Vibrio cholerae.

• The main symptoms are watery diarrhea and vomiting. This may result in dehydration and in severe cases grayish-bluish skin.

• Transmission occurs primarily by drinking water or eating food that has been contaminated by the feces

So how is our water purified ?

Self check #1

Answer the following

Multiple Select

Which of these codes are the main reference documents useful for this topic

• G13

• G12

• AS3500.1

• AS5601

• G1

Multiple Choice

What action led to the contamination of the water supply in London

• Dumping the waste into the sewer system

• Dumping the waste into the river Thames

• Dumping night soil underneath their floorboards

Multiple Select

What are the main symptoms of cholera

• Headaches

• Vomiting

• diarrhea

• dehydration

Pipe materials & components must meet listed standards.

Table 1 G12 lists relevant standards.

• •Polybutene  AS/NZS 2642

• •Copper NZS 3501

  •Galvanised steel NZS/BS 1387

  •Or other Proprietary

  system

• Cold only

  •PVC-U AS/NZS 1477

  •Polyethylene NZS 7601

Material selection considerations

• Most Plastic pipework requires protection from UV light

• Different materials and fittings provide different flow rates 

• Expansion allowance will depend on pipe selection

• Temperature ratings of system

Check this system out

Material selection considerations

• 50 year guarantee required if installed under a concrete slab NZBC

  B2, 15 years if covered, 5 years if exposed.

• Some environments may aggressively corrode metallic pipework

• Pressure rating

• Frost protection

Linear Expansion of Materials

Take a look on this graph of the different expansion rates

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Pex vs Copper

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Water service AS/NZS3500.1

• •Starts at the property boundary

• •Separate Isolation valves are also required where supply pipes enter a multi-unit dwelling.

• In NZ the meter and toby are usually

  owned by the Council / Network Utility. 

Self Check #2

Answer the following

Multiple Select

Select the pipe materials that must be protected from UV light

• PEX/AL/PEX

• Polybutene

• Crosslinked Polyethylene

• Copper

• Uponor ProPex a/b/c

Multiple Choice

What standard must galvanised steel pipe and fittings meet to be able to be used as per NZBC

• NZS/BS 1387

• NZBC G12

• AS3500.1:2021

• NZS 3501

Multiple Choice

Where is the start of the water service in AS/NZS3500.1

• Property boundary

• At the toby

• At the customer side of the water meter

Multiple Choice

What would be the design working pressure rating of Polybutene-1 Pipe if used on a system operating at 60*C

• 1050 kPa

• 880 kPa

• 60 PSI

• 105 PSI

Multiple Select

According to NZBC B2, what guarantee is required for a pipe that is exposed

• 10 years

• 5 years

• 50 years

• As per the warranty of the pipe system

Water Pressure / Hydrostatics

Water Pressure / Hydrostatics

• Pressure is a force exerted at any point in a body of water by the weight of the water above. 

• It is a direct result of the force of gravity, and acts in all directions simultaneously. 

• It has nothing to do with the actual volume of water, only the height of

  a ‘free body’ of water. Head. 

^{In general terms, the greater the head, or the higher the surface of the water above an opening the greater the pressure.}

Meters Head / Pressure Head

1m head = 9.81kPa

Gravity = 9.81m/s at sea level

Approximation 1m head = 10kPa

Hydraulic Gradient Low pressure supply issues

The hydraulic gradient is an imaginary line which determines the available pressure (head) at points above a main delivery pipe. 

 It only exists when water is flowing through that pipe

Flow rates will depend on supply pressure and flow restrictions within the system such as:

• Elbows & length of pipe runs

• Valves & components 

• Smoothness of pipe bore

• Blockages

-Minimum flow rates are listed in G12 Table 3 pg 26

Self check #3

Answer the following

Multiple Choice

How much pressure in kPa is exerted at 2.5 meters head

• 25 meters

• 2.5 kPa

• 0.25 kpa

• 25 kPa

• 250 kPa

Multiple Choice

Pressure is a force exerted at any point in a body of water by the weight of the water below

• TRUE

• FALSE

Multiple Choice

What is the acceptable flow rate in liters/ min for a hot tap on a laundry tub.

• 1.2

• 12

• 0.2

• 6

Multiple Select

Select all that apply that create flow restrictions in a system

• Pipe brands

• Elbows, Tees & valves

• Velocity

• Small branch runs

• All

Pressure Testing requirements

• Pre-flush your system to remove debris and contaminants

• Isolate taps and appliances not rated for the test pressure by bridging them out

• Use G12 - 7.5 pg. 40 - 1500kPa for not less than 15 minutes, and inspect system for leaks.

• NOTE: Some manufacturers require you to perform a different or elevated test, "PPR systems" for example

• Or use AS/NZS3500.1 – 16.3 pg. 89 – 1500kPa for not less than 30 min

• Once on test arrange for your TA inspection – pre line plumbing test

Commissioning

Once your preline plumbing test and final fit off are complete you will need to commission the appliances.

Testing & commissioning are two different processes. Also see your study guide.

During your commissioning process you will need to check/ record the operational performance of:

• Valves: for correct operation and orientation

• Cisterns: for correct fill & empty times including the correctly adjusted float levels see NZBC G1

• All Pressure relief valves: (CWE's, Vacuum , TPR's). Make sure you ease the levers on reliefs and that they shut off properly

• •Noise / water hammer issues: check that the water flow rate & velocity is correct, clip any loose pipework

Commissioning (continued)

• Flow rates: measure & adjust your appliance flow rates to comply with G12

• Stored water temperature: remember that if your stored hot water temperature is not correct you may not be able to achieve the tempered output required.

• Hot water delivery temperature: please make sure your delivery temperature is correct and that the TLV fails safe as per manufacturers manual

• 
  

Commissioning (continued)

Finally, there may be more components or appliances to check depending on the system installed. Once you have finished commissioning do a final check over the whole system to ensure there are no leaks and that everything works correctly. The main factor is, ALWAYS follow the manufacturers literature for guidance.

Self Check#4

Answer the following

Multiple Select

During your commissioning process you discover that the hot water temperature from the TLV is incorrect. What should you do next? (select all that apply)

• Change the TLV for a new one, it must be faulty

• Check the supply pressure

• Check the stored hot water temperature

• Make sure it is in the correct orientation

• Check the cold water temperature, it may be diluting the hot water too much

Multiple Choice

What is the recommended fill time for a cistern after the previous usage

• 1 minute with a supply pressure of 50 kPa

• 2 minutes

• 3 minutes with a supply pressure of 500kPa

• The time set by the manufacturers valve

Multiple Select

While commissioning you hear a loud judder and banging noise from the system when you turn off the taps. How could you alleviate this problem? (select all that apply)

• Clip any loose pipes

• Turn the incoming pressure down

• Clean any filters/ strainer

• Check and regulate the flow rates

Trade Science

Hard & Soft water

• Hard water leads to the buildup of limescale, which can block plumbing pipework and promote galvanic corrosion

• Hard water will not lather soap and can form scum when mixed with shampoos and detergents.

• Hardness in water is caused by dissolved salts. The main hardness causing ions are Calcium (Ca2+), Magnesium (Mg2+) and Bicarbonate (HCO3-)

Hard & Soft water (continued)

• These ions or minerals crystallise as a rock hard scale in the water causing scaling of pipes, valves, elements and heat exchangers. 

• Softening units offer a water purification solution for hard water and lime scale removal.

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pH scale

This scale shows the acidity and alkalinity

De-Zincification

Is a form of corrosion and weakening of brass objects in which zinc is dissolved out of the brass alloy.

Always use DZR fittings when connecting to disimilar metals

Well done!

Thank you for completing this lesson