1. Presented by

2. The course you are attending is:
PLUMBING AND GAS FITTING
Sizing of consumer piping

3. Introduction to the Course
Aims:
To be able to size gas pipework correctly

4. All must be installed to current standards and legislation
Assessment criteria
Locate, interpret and apply relevant information, standards and specifications to for the determination of requirements and the design of consumer piping systems
Apply safety requirements throughout the work sequence, including the use of personal protective clothing and equipment
As a minimum, from scaled plans/drawings, size consumer gas piping systems of at least one of them being a two stage LP gas system, ensuring:
Correct identification of sizing requirements of proposed piping system
Correct selection and use of appropriate processes, tools and equipment
Completing all work to specification
Compliance with regulations, standards and organisation quality procedures and processes.
Communicate and work effectively and safely with others.
All must be installed to current standards and legislation

5. Importance of correct pipe sizing
The procedure set out is for pipe sizing specifically for Gas.
This section deals with pipe sizing. As you maybe aware it is very important to achieve correct combustion at the appliance; this is achieved by having the correct amount of air/gas ratio.
By making sure the pipe size is correct in the first place, you have a good chance of having the correct flow of gas.
If you have an incorrectly sized gas pipe this could cause the appliance to be inefficient and therefore not meeting the customer’s expectations, and worse case scenario incomplete combustion causing CO.
To avoid these situations we need to take into account the gross heat inputs of all appliances fitted on the system. There is an allowable pressure loss due to resistance within the pipe work this loss is dependent on type of tube and pressure available.
Natural Gas appliances are designed to operate with an inlet pressure of 1.25KPa and LPG 2.75KPa

6. Information Required Prior To Pipe Sizing1.
The type of gas to be used in the installation, e.g. natural gas or LPG, 2.
The gas consumption of each appliance in Megajoules per hour (MJ/h) 3.
The operating pressure of the installation, e.g kPa or 2.75 kPa. 4.
The maximum allowable pressure drop in the pipe work from the meter or cylinder outlet to any appliance. (See table below). 5.
The proposed layout of the consumer piping system, including all pipe lengths, and the location of each appliance.
Gas type
Pressure drop
Natural gas
0.12 kPa
Low pressure gas
0.25 kPa
Other gases
0.075 kPa
Liquid petroleum gas
3.75 kPa
TLP

7. Typical appliance sizes
TYPICAL GAS RATES (MJ/HR)
WARM AIR HEATER 40
COOKER 40
MULTIPOINT WATER HEATER 100
GASFIRE/SPACEHEATER 20
STORAGE WATER HEATER 35

8. Method Of Pipe Sizing
Step I. Sketch The Consumer Piping Layout
Step 2. Mark The Position Of The Meter or Cylinders and Appliances showing gas
consumption
Step 3. Note The Length Of Each Pipe Section and Branch, rounded up to nearest metre,
Step 4. Identify The Branch and Appliance Points and mark Use A, B, C, etc.
Step 5. Determine The Main Run, see Next Slide

9. Information Required Prior To Pipe Sizing
Step 6. Select the Pipe Material or Materials
Step 7. Select the Pipe Sizing Table AS5601

10. AS5601

11. Water Heater
Cooker 1m
Fire 2m M 2m
4.5m 2m 2m

12. M Combi 1m 2m 1.5m 0.5m Storage water heater Cooker Fire Wall Heater
Space Heater
Space Heater