Design and size heated and cold water services and systems

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3 ACKNOWLEDGEMENTS National Plumbing Services Training Advisory Group Plumbing Industry Commission Victoria Commonwealth of Australia 2015 Construction and Property Services Industry Skills Council PO Box 151 Belconnen ACT 2616 Tel: This work is copyright, but permission is given to trainers and teachers to make copies and contextualise the resources for use within their own training organisation or in a workplace where training is being conducted. This permission does not extend to making copies for use outside the immediate training environment for which they are made, or the making of copies for hire or resale to third parties. The work was first published in 2006 with the assistance of funding provided by the Commonwealth Government, through the then Department of Education Science and Training (DEST). The 2015 publication has been updated to reflect changes to the national units of competency. The views expressed in this work do not necessarily represent the views of the Commonwealth of Australia or CPSISC. In addition, the Commonwealth of Australia and CPSISC do not give warranty or accept any legal liability in relation to the content of this work. The website addresses and other contact information provided in this publication were compiled in good faith and were correct at the time of printing. The updating of these resources was completed by: National Plumbing and Services Training Advisory Group, with funding and support provided by the Construction and Property Services Industry Skills Council (CPSISC): This guide was developed in consultation with representatives of the Plumbing Industry by NPSTAG and CPSISC to support the implementation of the CPC08 Construction, Plumbing and Services Training Package. Commonwealth of Australia

4 Acknowledgements Project reference committee: Writer: Technical editor: National Plumbing Services Training Advisory Group Ivan Filsell Adrian Clarke and Lyle Kelson Instructional designer: Graphic artist: Word processor: Marian Jaquiery Laura Bito Melissa Rogers 2 Commonwealth of Australia 2015

5 Contents ACKNOWLEDGEMENTS... 1 Before you begin Planning your work Planning issues Tools and equipment Working with others Workplace requirements WHS and PPE Environmental issues Water supply systems Types of water systems Water system temperature guidelines Materials Sizing water services/systems Sizing procedure for external pipework for a water service External pipe sizing procedure summary Sizing procedure for internal pipework for a water service Internal pipe sizing procedures summary Cross connection and backflow Pipework installation Cold water supply service Options Hot water systems Types of hot water systems Hot water systems and energy sources Insulation in hot water systems Hot water systems for multiple dwellings Hot water systems for commercial and industrial applications Pipe sizing for mains pressure hot water systems Warm water systems Commonwealth of Australia

6 6.1 The need for warm water systems Methods for providing warm water Regulatory requirements for warm water systems Planning fire systems Fire system terminology Types of fire systems Fire brigade booster connection Fire hydrant pipework installation Testing and commissioning fire hydrants Hose reel installation Flush valve system Types Flush valve connected to the drinking water Flush valve supplied from a break tank Restoring work area Documentation Site clean-up and restoration Final assessment activity Commonwealth of Australia 2015

7 Before you begin Welcome Welcome to the learning resource for the unit Design and size heated and cold water services and systems. This resource will help you develop the knowledge and skills you need to demonstrate competence in this unit. A learning resource such as this is not intended to be the only source of information you use to develop skills and knowledge in the unit it relates to. Your trainer, instructor or supervisor will provide you with additional information and information sources throughout your training. Flexible delivery Your trainer, instructor or supervisor for the unit may adapt and deliver this learning resource as required to suit people from a range of backgrounds and in diverse learning environments (such as rural and isolated settings). This will assist in meeting equity principles and conforming to legislative policies. How to use this resource This resource addresses the underpinning knowledge and skill development required to help you plan, size and document the layout of hot and cold water services and systems for multi-floor buildings. It contains: information on planning, sizing and documenting the layout of hot and cold water services activities designed to encourage you to check and confirm your learning along the way and to help you complete the final assessment a summary of the final task or tasks you must complete to be assessed as competent in this unit. Your assessor will give you additional specific detail required for your final assessment activity in line with state and territory regulations and industry requirements. Commonwealth of Australia

8 The resource has been developed for use in a variety of ways. Your trainer, instructor or supervisor will advise on how best to use it during your training, which may include: teacher-centred, class-based study home-based, self-directed study activities in the workplace. To complete the unit Design and size heated and cold water services and systems you may be required to: read the information in this resource complete the resource activities as directed and submit your answers for review or discussion with your trainer, instructor or supervisor work with your trainer, instructor or supervisor to practise planning, sizing and documenting the layout of hot and cold water services read the final assessment summary together with any additional assessment information your assessor provides complete the final assessment. Your assessment in this unit It is important to note that the role of the assessor in assessing units of competence is quite separate from the role of trainer, instructor or supervisor. Your assessor for this unit may or may not be the same person as the trainer, instructor or supervisor who worked with you during your training. However, your assessment must always meet the requirements of the unit. You will find references to trainers, instructors or supervisors and assessors throughout this resource depending on the context. Assessment in this unit will require you to demonstrate the skills and knowledge needed to carry out work based risk control processes. Table 1 on page 3 suggests the variety of assessment methods that may be used to assess your competence in this unit. In many instances, your assessment may involve a combination of methods to ensure the validity, reliability, flexibility and fairness of the process. If you have any questions about your assessment please discuss them with your assessor who will decide with you the specific details of what you will do. An assessor may develop specific assessment strategies to meet the particular requirements of learners from diverse backgrounds. This unit may be assessed in conjunction with assessment for other units of competence. In such a case assessment might be based on a task or tasks related to a project that more closely resembles workplace activities. An appropriate unit for such project-based assessment might be one that naturally forms part of your workplace responsibilities and roles. Your assessor will decide if you are to be assessed in this way and will advise you. 6 Commonwealth of Australia 2015

9 Assessment methods Key Assessment method Description QS Questioning oral/written Assessor will ask a range of questions from a moderated bank of questions that support the underpinning skills and knowledge required to achieve competency in this unit. Questions may be answered in written or oral form. WN Written notes Learner will complete written notes, activities or student resource materials to support the achievement of underpinning knowledge required to achieve competency in this unit. TB Test bank Learner will complete computer test bank assessment which supports the underpinning skills and knowledge required to achieve competency in this unit. PO Practical observation Assessor will observe the learner completing practical task(s) that meet the assessment criteria to the required specification in the workplace. DM Demonstration Assessor will observe the learner completing practical task(s) that meet the assessment criteria to the required specification in a simulated work environment. CS Case study/project Learner will complete workplace-based projects or case study reports to support the underpinning skills and knowledge required to achieve competency in this unit. LB Logbook Learner will provide evidence of practical work and/or assessment tasks completed at the workplace via personal logbook. 3P Third party report Assessor will seek report from learner s workplace employer, supervisor or other approved party on the performance of a learner in the workplace against assessment task criteria and requirements of the unit. WD Workplace documents Learner will provide copies of workplace documents to support the underpinning skills and knowledge required to achieve competency in this unit. Table 1 Assessment methods Commonwealth of Australia

10 Prerequisite units There are no prerequisite units for this unit. Additional resources The following resources have been suggested that may help you undertake training and assessment in this unit. Your trainer, instructor or supervisor may also recommend specific books, videos and DVD s. Note Standards, websites and codes of practice change so it is important to keep up to date. Make sure you always have the most recent edition of the standards applicable to your current job. You should also obtain relevant manufacturer information. Texts Building Code of Australia Plumbing Code of Australia AS/NZS 3500 Plumbing and drainage AS Fire hydrant installation AS Installation of fire hose reels AS/NZS Fire hose reels Websites Video or audio resources 8 Commonwealth of Australia 2015

11 1. Planning your work Water supply to buildings is a complex task because buildings are as variable as are the requirements of the end user. Buildings may vary from single storey domestic to multi-storey commercial complexes. The water supply may include hot and cold water, warm water at a constant temperature, a flush valve system and a hydrant/hose reel system. The water required by these systems may come from a range of sources such as a reticulated town supply or from rainwater storage tanks. Other variables that must be catered for are a range of available water pressures and changes in volume due to rises or falls in temperature. This resource provides you with information on identifying the job requirements, planning the work, sizing and documenting the layout of hot and cold water supply in multi-level buildings up to a height of ten floors. The key to any successful project is good preparation, accurate identification of the job requirements, proper sequencing of activities and effective completion of the job. As the plumber engaged to plan hot and cold water systems you need to research information, source equipment and calculate sizes and quantities of materials. The procedure can be summarised in the following steps: identify the job requirements plan the work sequence plan the system layout complete the documentation complete end of job procedures. Before you can plan your work you need to know who you will be working for and who will be supplying the contract documents. You could be: working directly with the client working for a contractor sub-contracting working with an architect or engineer working for a local water authority or council other. Having established who you are working for and obtaining the contract documents you can proceed to plan you work. Commonwealth of Australia

12 1.1 Planning issues The following table provides a summary of the planning issues you may need to consider prior to preparing the water system layout for a residential building of six floors. This list is not exhaustive. There may be other issues that you need to consider for specific projects. Planning issues Ask these questions before you prepare a system layout Project specifications Who will supply the job specification and drawings? Who will supply the building specifications and drawings? What types of appliances are to be used? Is power required for appliances? How much potable or non-potable water is required? How many fixtures are required? Location? Have installation requirements been specified, and are variations possible? Have alternatives been investigated? What are the filtration and/or backflow prevention requirements? What system will best suit the specifications? What type of pipe will best supply the correct flows/pressures? 10 Commonwealth of Australia 2015

13 Planning issues Ask these questions before you prepare a system layout Site details What are the surrounding site conditions (concrete, asphalt, gardens etc)? What physical measurements need to be taken? What type of water supply and pressures are available? How will the water be supplied to the specific areas? Can a site visit be arranged? What on-site or off-site parking is available? Documentation Have copies of relevant regulatory requirements been obtained? Working with others Have details of the latest product information and specifications been obtained? Have all available updated plans and specifications for the project been obtained? Contact others you may have to work with such as the local council, project manager, relevant water authority, product supplier/manufacture and those involved in other trades related to the project. Site office Will I have a planning area on site or will I have to create a suitable space? Resource requirements Will I be required to plan away from the site? What are my staffing requirements? Will l have computer access? Do I require planning software/ computer programs? What tools and equipment are required for the planning task? What tools and equipment will be required for installation? Commonwealth of Australia

14 Planning issues Ask these questions before you prepare a system layout WHS Do I need a site induction? 1.2 Tools and equipment Do I need a card or other entry permit? What are the potential hazards and risks on site? Have I completed a safe work method statement/jsa? What PPE will be required for the job and to work on the site? Most water supply installations will require a standard plumber s tool kit of hand tools and small power tools. Where the job requirements dictate specialist tools and equipment such as welding, threading or metal forming, these should only be used after adequate training or instruction. Each site is unique and the use of tools and equipment must comply with safe work practice and site specific procedures. 1.3 Working with others Almost all plumbing work involves working with others. For a small job this may be as simple as the plumber and the client but most projects require working with many others. These may include the local council or water authority, the client, the main contactor or sub-contractor, other related trades, equipment suppliers, materials suppliers and delivery personnel. On large and complex projects the list may be much longer. To work successfully with others it is important to have a cooperative approach and to follow these steps: make a list of relevant contact persons at the planning stage confirm details for contact persons such as phone numbers and location 12 Commonwealth of Australia 2015

15 make preliminary contact with relevant people before job commences to confirm job starting time and site procedures outline to relevant people job requirements and construction sequence coordinate with other trades and others affected by the work to ensure smooth running and planned progress check with supervisor or relevant authority on testing and completion of work on completion of work clean site and remove all materials and equipment and confirm with others involved that correct procedures have been followed. 1.4 Workplace requirements Each workplace is different and will have some requirements that are special to that site. These special requirements will need to be taken into account at the planning, installation and documentation stages of the job. Some examples of workplace requirements are: ground conditions may be unsuitable for copper pipe extensions or modifications to existing work will require consideration of compatibility of materials the documentation procedures such as how many copies and who holds them can vary according to the site, the contractor and the client. It is common to make approved minor modifications to the design as jobs progress. These changes should be recorded on the as built drawings and filed in accordance with the workplace requirements. Commonwealth of Australia

16 1.5 WHS and PPE Working on any construction site requires the use of adequate personal protective equipment (PPE). The minimum requirement consists of protective clothing, work boots, head protection, hearing protection, eye protection, hand protection and appropriate weather protection. In addition job specific and site specific requirements must be complied with. Workers on site should also be aware of how to handle hazardous materials as these may be found on the site. Workplace Health Safety (WHS) requirements for all work sites must be complied with. These are dictated by the relevant WHS Acts and by relevant WHS codes of practice. Note that the requirements may differ slightly between states and territories. Workers on site should be aware of the regulations that apply to them. Only safe work practices should be employed for the safety of all workers and the general public. Particularly with the installation of larger water service systems in multistorey buildings specialist equipment may be required such as scaffolds, hoists, lifts and cranes. This equipment should only be used by those who have been adequately trained and authorised. 1.6 Environmental issues The main environmental concerns associated with hot and cold water services are possible damage caused when laying pipes, uncontrolled discharge of waste water and the inappropriate disposal of surplus and waste materials. When pipes are laid the trenches must be backfilled and the surface reinstated in accordance with the specification. Delays or poor workmanship may lead to erosion problems. Hot and cold water system waste is normally connected to a suitable drainage system but should there be temporary flows from testing, backwashing or other procedures these flows should be directed to a drainage system in a way that will not cause erosion or other environmental problems. A system of baffles, soak-away or filters may be required to protect the environment. Other environmental issues that should be considered by the workers on site include noise pollution that may affect neighbours, tree damage and the recycling of site materials. 14 Commonwealth of Australia 2015

17 Waste and surplus materials must be recycled or removed from the site in accordance with site clean-up procedures. However, accidental hazardous spills (for example chemical or oil) and the removal of hazardous materials (for example asbestos) are also environmental issues that may be faced. The site must comply with any requirements specified by the Environmental Protection Agency. Commonwealth of Australia

18 2. Water supply systems Water supply systems are as varied as the situations they may be required for, eg the supply of reticulated mains pressure water to a single house or the supply of water to a stock trough from a dam. All water supply systems have a source, a means of delivering the water through a pipe or network of pipes, and a point of discharge or storage. The Australian/New Zealand Standard AS/NZS Plumbing and drainage Water services, sets out the requirements for the design and construction of cold water services from the water main to the points of discharge and for multiple units and multi-storey supply installations. 2.1 Types of water systems Water systems may include the following. Domestic house: Potable water is supplied from the water main to the property boundary via a property service pipe, through an isolating valve and metering assembly, then on to the house and its fixtures (bath, basin, sink, hose bib etc) via pipe work referred to as the water service. Multiple living units: Potable water is supplied from the water main to the property boundary via a property service pipe, through a control valve and metering and testing assembly, (determined by the size of the property service required to supply the units and facilities with the appropriate supply of water), then on to the units, their fixtures and appliances. Interconnected water services (for large water services): There may be the need to supply more than one water service to a hospital, school or large factory requiring a large or constant supply of water. Multi-storey constructions: Potable water is supplied from the main to the property boundary, through control valves metering and testing assemblies, pumps or storage tanks to the fixture outlets at multiple levels of the construction. Non-drinking water services: Non-potable water is supplied from the point of supply to the point of discharge. These supplies may be recycled or reclaimed water, eg a car wash facility. 16 Commonwealth of Australia 2015

19 Flushing systems for sanitary fixtures: Water is supplied to storage tanks mains pressure water is used for flushing sanitary fixtures. Water heating system: Water is supplied to the system and the heated water is delivered to fixtures or appliances by gravity recirculating, pumped recirculating, un-vented bulk hot water or mains pressure storage hot water systems. 2.2 Water system temperature guidelines Temperatur e Classification 0 to 25 C Classified as cold water. 25 C to 50 C Classified as warm water. The outlet delivery temperature should not exceed 45 C at ablutionary fixtures. 50 C to 70 C Classified as hot water. If held in storage the temperature cannot be less than 60 C. The outlet delivery temperature should not exceed 50 C at ablutionary fixtures. 70 C to 90 C Classified as high temperature hot water. It is usually delivered to commercial appliances at 82 C. The following table shows the behaviour of water at standard atmospheric pressure of kpa. Temperatur e Behaviour 0 ºC Fresh water freezes 4 ºC Maximum density 16.6 ºC Standard temperature -2.2 ºC Sea water freezes 40 ºC Hot bath water 50 C Maximum supply temperature to bathrooms and ensuites for new installations 100 ºC Boiling point Commonwealth of Australia

20 Formula This formula can be used to calculate the expansion of water: E = L x t x c Where: E = expansion of water in litres L = litres of water contained in cylinder t = temperature rise of water in degrees Celsius c = co-efficient of expansion of water ( ) Example Calculate the amount of water expansion that would occur if 280 litres of water was heated from 16 C to 70 C. E = L x t x c E = 280 x (70-16) x E = 280 x 54 x E = 5.67 litres Answer: 5.67 litres of hot water would be discharged from the temperature and pressure relief valve if no water was used during this heating process. 18 Commonwealth of Australia 2015

21 Example To calculate water pressure: Water pressure = P = m x 9.81 kpa If 1 litre of water at 4 C has a mass of 1,000 g and 1 m 3 contains 1,000 L, 1 m 3 of water has a mass of 1,000 kg. This mass subject to gravity has a weight or force of 1,000 x Therefore, 1 m head of water exerts pressure of 9.81 kpa. Example: A column of water 20 m high 20 x 9.81 = kpa 2.3 Materials A large variety of approved materials are available to the plumbing industry for use in water supply systems. Each has its own qualities and affects the water it transports differently. The installation and selection of materials to be used on a water supply service is the responsibility of the licensed plumber. However local water supply authorities nominate the codes and standards as well as identifying specific features of installation which may be relevant to their area. You will need to attach to your layout plan a list of all materials needed to carry out the plan. Selecting materials The flow rates and head loss associated with the different materials and fittings should be available from the manufacturer or the supplier. These are normally in the form of a graph or chart. The resultant flow rates/pressure losses can be calculated depending on pipe lengths, fitting size, available pressures, and/or flow rates. This can be a huge task in some plumbing applications and so computer based hydraulic design programs help the hydraulic engineers and designers significantly. Any material used in water supply systems must meet the minimum requirements of AS/NZ : Section 2. Commonwealth of Australia

22 Optimising materials Pipes sizes and materials should be selected in accordance with job requirements, the specification and the standards, and the following points should be considered: under-sizing of pipes will lead to inadequate performance of the finished system over-sizing of pipes will lead to considerable extra cost multiple material types may introduce compatibility problems. Consequently it is important to stick to the size suggested by the design charts and tables and to minimise the material types used on any one job. 20 Commonwealth of Australia 2015

23 3. Sizing water services/systems Pipe sizing is of extreme importance for the correct flow and pressures required at an outlet. In order for this to be achieved the plumber/ designer must have a basic knowledge of the criteria for pipe sizing. 3.1 Sizing procedure for external pipework for a water service External pipework will include pipework connected at the authority s water main to a point in the pipework system before it enters the building structure to supply fixture outlet points. Reading You should now read AS/NZS : Water supply section on Sizing of water services. Take particular note of the following: scope of section probable simultaneous demand pressure requirements available pressure pressure at outlets head loss velocity requirements table probable simultaneous demand (PSD) for multiple dwellings pipe size limitation. Commonwealth of Australia

24 Activity 1 1. Who determines minimum and maximum pressures at the water main? 2. Name the unit of measure used to express mains pressure. 3. State the minimum working pressure at the most disadvantaged outlet point. 4. What is the water velocity requirement in supply pipework for dwellings? (Use table 3.2.) 5. What is the probable simultaneous demand (PSD) for pipework supplying nine dwellings? Water pressure can be expressed in kilopascals and metres head. Formula P = H x 9.81 Where P = pressure in kilopascals (kpa) H = height or head of water above outlet 9.81 = a factor 22 Commonwealth of Australia 2015

25 Example Convert 500 kpa to metres head P = H x 9.81 Transpose: H = P 9.81 H = H = metres Therefore, 500 kpa = metres head. Your trainer will provide you with additional activities related to pressure and head. Reading You should now read AS/NZS : Water supply appendix on Sizing method for supply piping for dwellings. Take particular note of the following sections: general information procedure worked example. Commonwealth of Australia

26 Activity 2 1. Explain how the index length is determined. 2. State all factors required to calculate the pressure drop. 3. State how the figures for the PSD are obtained. 3.2 External pipe sizing procedure summary Follow these steps to size external piping: 1. Determine the index length (to be used for all calculations). This is the distance from the main to the furthest outlet of the installation. 2. Determine the pressure drop (to be used for all calculations). To do this the plumber will need to determine main pressure, static head, and minimum outlet pressure. 3. Determine the flow rate (L/sec for each pipe section) by determining the number of units being supplied by that pipe line and then referring to the AS/NZS table on Probable simultaneous demand (PSD) for multiple dwellings to give the appropriate flow rate. For example, 10 units = 1.74 L/sec. 4. Using the AS/NZS appendix Sizing method for supply piping for dwellings table Pipe sizing for maximum velocity of 3 metres/sec, choose the appropriate table for the pressure drop allowed. If the pressure drop does not line up exactly, then choose a lower pressure drop (drop down). 5. Choose the appropriate index length column and use this for sizing the entire external installation. If the index length does not match, choose the next length up (index up). 6. Using the flow rate already calculated in step 3, follow the column down until you find a flow rate equal to or greater than the one required. 7. Now move horizontally across to the first column to give you the pipe size for that flow rate. Your trainer will provide you with additional activities related to sizing external pipework. 24 Commonwealth of Australia 2015

27 3.3 Sizing procedure for internal pipework for a water service Internal pipework will include pipework connected at the authority s water main to the most distant fixture outlet in the building. Reading You should now read AS/NZS Water supply section on Sizing of water services. Take particular note of the following sections: flow requirements flow rates at outlets loading units table flow rates and loading units probable simultaneous flow rate pressure requirements available pressure pressure at outlets head loss velocity requirements table probable simultaneous flow rates (PSFR) pipe size limitations property service branch off takes. Now read AS/NZS : Water supply sizing Appendix on Sizing of piping for dwellings. Take special note of the following sections: general procedure worked example. Commonwealth of Australia

28 3.4 Internal pipe sizing procedures summary Follow these steps to size internal piping: 1. Determine the index length (for each individual unit). This is the distance from the main to the furthest outlet of the unit concerned. 2. Determine the pressure drop (for each individual unit). To do this the plumber must determine main pressure, static head of the unit, minimum outlet pressure. 3. Determine the flow rate (L/sec for each pipe section). If the pipe section supplies only one fixture, the flow rate is taken from table 3.1, column 2, eg shower = 0.22 L/sec. If the pipe section supplies more than one fixture, each fixture is given a loading unit from AS/NZS , table Flow rates and loading units. The loading units of each fixture supplied by that pipe section are then added together. This total loading is read off AS/NZS , table Probable simultaneous flow rates (PSFR) to give you the probable simultaneous flow rate for the pipe section. For example, a shower = 2 loading units and a bath = 8 loading units. A pipe section supplying these two fixtures would then have a loading of = 10. The probable simultaneous flow rate for this pipe section is obtained from AS/NZS , table Probable simultaneous flow rates (PSFR). That is, 10 units = 0.26 L/sec. Point to note At no time should the pipe size be smaller than the inlet pipe of the fixtures it supplies. 26 Commonwealth of Australia 2015

29 3.5 Cross connection and backflow Whenever there are cross connections from one part of the system to another there is a possibility of backflow and, hence, possible contamination. To prevent this it is necessary to rate the cross connection hazard and install the appropriate protection measures. Reading Read about cross connection control and backflow prevention in AS/NZS section on Cross connection control and backflow prevention. Particularly note: protection of water supplies cross connection hazard rating provision of backflow prevention devices suitability of devices for hazards installation of backflow prevention devices. Generally all backflow prevention devices have: full flow isolation valves installed both upstream and downstream of the device a line strainer fitted upstream to protect the device a demountable joint fitted upstream and downstream to allow the removal of the device for servicing or replacement (on occasion, when necessary) a water hammer arrestor fitted upstream to protect the device a tundish fitted when water discharge from the device is liable to cause damage. Not all backflow prevention devices can be used to protect the previously stated cross connection hazards. For example, an area deemed to be a high or medium hazard cannot be protected by a device which is suitable for a low hazard only. In simple terms, only devices that are testable can be used in high and medium hazard areas. Commonwealth of Australia

30 The following table distinguishes between the suitability of the devices. Suitability of devices Testable backflow prevention device Crossconnection hazard rating Protect against backpressure Registered break tank (RBT) Registered air gap (RAG) Reduce pressure zone device (RPZD) Double-check valve assembly (DCV) Pressure type vacuum breaker (PVB) High/medium/low High/medium/low High/medium/low Medium/low Medium/low Backflow prevention devices that are provided with test taps for the purposes of testing the operation of the devices. Yes Yes Yes Yes No 28 Commonwealth of Australia 2015

31 3.6 Pipework installation When installing pipework, you must do so safely and without interruption or damage to other services. Installation zones and minimum clearance distances must be strictly adhered to. Reading Read about the installation of pipework, governed by AS/NZS section on Installation of cold water services. Take particular note of: electrical safety precautions and earthing proximity to other services isolating valves location of piping. Note that the AS/NZS : Water supply Installation of cold water services Concealed pipework states that, in relation to the location and access within and under buildings, water service pipes shall not be embedded or cast into concrete structures. Storage tanks Storage tanks may be the sole source of water supply in some instances, or they may be used to supplement or balance a supply from another source such as a town supply. Where water storage tanks are to be used as part of a water supply system, installation must comply with AS/NZS , the section on Water storage tanks. In some situations, where water storage tanks may be used is also determined in the standard. These are listed below: Non-drinking water Cold water services may include non-drinking water for some purposes such as flushing toilets, garden watering, recycling and some commercial processes. It is vital that drinking water does not become contaminated. For this reason any non-drinking water installation must comply with the section on Non-drinking water services. Commonwealth of Australia

32 Sanitary flushing Where a cold water service is provided for sanitary flushing purposes the installation must comply with the section on Water for sanitary flushing the section on Water storage tanks. Examples There are some worked examples in AS/NZS : Water supply Installation of cold water services. Your teacher will also work through the relevant sections of the standard and provide exercises and examples. See your trainer for additional activities related to the installation of pipework. 30 Commonwealth of Australia 2015

33 4. Cold water supply service 4.1 Options There are a number of ways to design a cold water supply service to suit the many different types of buildings and in various situations: mains pressure mains pressure with a storage tank mains pressure boosted (hydro-pneumatic system) mains pressure boosted (pneumatic) mains pressure boosted (with a storage tank) mains pressure boosted (hydro-constant). Mains pressure Where the mains pressure is sufficient to provide a constant supply of water at all times to all fixtures, direct connection to the mains is possible. Mains pressure with a storage tank In cases where mains pressure is sufficient for some periods of the day to raise water to the top of the building, a storage tank can be installed. This tank will hold enough water to supply the building s needs during those periods when the mains pressure is inadequate. This system is not commonly used because it is possible to use all the stored water before the tank refills. Commonwealth of Australia

34 Mains pressure boosted (hydro-pneumatic system) A centrifugal pump on the service pumps water to a closed vessel. This in turn compresses the air inside that vessel. When a tap is opened, water flows from the vessel, delivered by the force of the compressed air. As the pressure drops below a pre-adjusted amount, a pressure actuated control switch turns on the pump. This in turn pumps more water into the vessel until a preset pressure is reached. This system can be used when only a small section of the building does not get supplied with water during peak periods. It may be used to pressure boost the upper floors of a building when the building is supplied by a storage tank on the top floor. Mains pressure boosted (pneumatic) By pressurising the closed vessel with compressed air from an air compressor, higher water pressure and less frequent pump cycles may be obtained. Mains pressure boosted (with a storage tank) Some authorities may require a break tank between the main and the pump to prevent possible contamination through a cross connection, eg an industrial laboratory. Also, where the boosted system reduces the pressure in the mains causing an inadequate supply to other users, the authorities may require a storage tank to be installed before the booster pump. Mains pressure boosted (hydro-constant) This system is similar to the storage tank and hydro-pneumatic systems but instead of using an air vessel, a fluid drive is fitted between the motor and the pump. The motor runs continually and a pressure sensor actuates the fluid drive for a smoother constant pressure (similar to the automatic drive in a motor vehicle). 32 Commonwealth of Australia 2015

35 5. Hot water systems Appliances used for heating water are provided in most domestic, commercial and industrial buildings. These appliances may be single point heaters such as sink heaters and bath heaters. Alternatively, they may be hot water heaters supplying a number of draw off points in one building. 5.1 Types of hot water systems The many types of hot water systems include: instantaneous mains pressure storage medium pressure valve controlled operation medium pressure cistern controlled operation electric heat exchange operation side fed displacement operation falling level type operation solar hot water heater boiler operation. Energy sources To heat water an energy source is required. This is covered in AS/NZS section 7, Energy sources. Sources include: controlled energy sources such as electricity supply, gas and oil uncontrolled energy sources such as wood or coal heaters. Commonwealth of Australia

36 Latent heat The terms used to describe the change of state from a solid to a liquid, for example, ice to water, are latent heat of liquefaction or fusion. The energy required to cause this change of state without a temperature rise is 330 kilojoules (kj) per kilogram (kg) of water. When water changes from a liquid to a vapour it is referred to as latent heat of vaporisation. The energy required to cause this change of state without a rise in temperature is 2,300 kj for each kg of water. The latent heat of vaporisation can be used by passing steam through a coil to heat water in an installation before returning back to the heating source for reheating. This is an indirect form of heating. The source for reheating will be either controlled or uncontrolled. Temperature Temperature is a measurement relative to the amount of heat in a body. The official scale used to measure temperature in Australia is the Celsius scale. Some overseas technical publications may indicate temperatures in the Fahrenheit scale. Freezing Boiling Celsius 0 ºC 100 ºC Fahrenheit 32 ºF 212 ºF 34 Commonwealth of Australia 2015

37 Formula C = 5 9 x (F - 32) Example Convert 212 Fahrenheit to a Celsius reading. C = 5 9 C = 5 9 x (F - 32) C = 5 9 x 180 C = C = 100 x (212-32) Answer: 212 F = 100 C Commonwealth of Australia

38 5.2 Hot water systems and energy sources The common features of a range of hot water systems are summarised in the table below. Further information is available from the following resources: Puffet R J & Hossack L J, Plumbing services, Volume 1, section on Hot water systems Rheem, Hot Water Manual, section on Types of water heating systems Rinnai Infinity, Hot Water Manual, section on Types of water heating systems. Heat transmission Forms of heat energy Features of hot water heating Conduction Convection Radiation Electricity Gas Solar Solid fuel Liquid fuel Vented Unvented Particle to particle Less dense particles rise, cooler particles drop Rays of heat in straight lines without heating space in between source and area being heated Natural, propane Sun Coke, wood Kerosene, oil, diesel Operate at low pressure, unaffected by hot water expansion, outlet pressure depends on supply, long life tanks Connected direct mains pressure, provision for expansion required, short life span storage cylinder Storage All hot water stored in well insulated cylinder, capacity variation of litres, large capacity off peak rates, small capacity constant heating 36 Commonwealth of Australia 2015

39 Non-storage Direct Little to no provision for storage, pay for hot water used on demand, less space for heater, usually high demand energy for short time 415 V Source of heat energy is in immediate contact with liquid being heated Construction materials Indirect Sheet copper, steel, glass lines, stainless steel, bronze Source of heat energy does not come in direct contact with liquid being heated Location Unlimited However, must comply with regulations of authorities Sacrificial anode Rod composed of magnesium alloys to suit water conditions of various areas Fitted to all glass lined mains pressure H/W tank Purpose is to protect the glass lined steel cylinder against corrosion should a fault occur in the glass lining 5.3 Insulation in hot water systems Attention must be given to reducing, as far as possible, the heat losses resulting from exposed hot water or steam pipes and ancillary equipment. Covering the pipes, etc with a non-conductor of heat will be necessary. A number of pipe coverings are available but the efficiency of such a covering depends mainly on the manner in which the intercises (air cells) are filled with air but not open enough to allow the air to circulate through it. Where hot water pipes are placed in casings special care is required to prevent the cold air passing in at one end and escaping at the other end, which has a cooling effect on the pipes. Reading Commonwealth of Australia

40 Now read AS/NZS section on Energy efficiency. This covers insulation requirements. Also read the clause Insulation of piping and fittings, which gives useful information on thermal insulation and the K factor. Thermal conductivity Conductivity is usually denoted by a term called the K factor. This is the quantity of heat transmitted through a substance (insulation material) from the hotter to the colder parts. The K factor is expressed as watts per metre per degrees Celsius difference between inside and outside temperature (watts/metre/ C). For example a DN 15 pipe would require 9 mm thick insulation with a K factor of 0.03 while the same diameter pipe would require 40 mm thick insulation with a K factor of Expansion All materials when heated will expand. Serious problems can be avoided in plumbing services if provision is made at the planning stage for the material to occupy a greater space when heated to a higher temperature. When water pipes change from cold to hot they expand and move. If there is no provision for movement, some part of the installation will fracture and fail. It is normal practice to build loops, bends and other expansion devices into the system to prevent potential failures. These provisions are covered in AS/NZS section on Installation of cold and hot water piping and controls. 38 Commonwealth of Australia 2015

41 Expansion valves, pressure relief and venting Changes in temperature also cause volume change in water enclosed in the system. Without special provision water tanks would burst when water expands or collapses as it contracted. To prevent these disasters a range of expansion valves, pressure relief valves and venting techniques are employed. Reading Now read AS/NZS section on Installation of water heaters other than solar heaters. Take particular note of the following: scope water heaters pressure relief and venting of water heaters in containers valves table requirements for valves and other fittings table set pressures for valves clause installation of valves clause temperature/pressure-relief and expansion-control valve drain lines figure typical relief drainage figure temperature/pressure relief valve drain lines common stack discharge method figure typical installation of valves figure typical installation of mains pressure water heater figure typical installation of pressure water heater controlled with pressure reducing valve. Further information on the following can be found in Rheem, Hot Water Manual, section on installation requirements and accessories : heater position cold water connection hot water plumbing temperature and pressure relief (T&PR) valves. Note: Other hot water service manufacturers also provide technical information relevant to their products. Commonwealth of Australia

42 5.4 Hot water systems for multiple dwellings Several methods can be used to supply hot water to flats, villas, home units and town houses, each of which has its merits. A typical multiple installation of pressure type storage water heaters is commonly known as the Equa flow system. Other systems include: individual water heaters for each living unit a central installation supplying several units from a central bank supply. Reading Read the following resources for relevant information: AS/NZS section on Multiple installations of pressure type storage water heaters AS/NZS section on The installation of water heaters other than solar heaters Rheem, How Water Manual section on Installation requirements and accessories, with particular emphasis on: multiple installation of storage water heaters return connection and recirculation system gravity recirculation, and pumped recirculation drainage from temperature and pressure relief valves (T&PR valves). Rheem, How Water Manual section on Selection of hot water heaters for commercial use. See especially the sections on Multiple dwellings, Individual water heaters, and Central installation. Refer to the following figures: direct feed for multiple dwellings split system for multiple dwellings packaged system for multiple dwellings pumped recirculation for multiple dwellings high level installation for multiple dwellings. 40 Commonwealth of Australia 2015

43 5.5 Hot water systems for commercial and industrial applications Commercial and industrial installations that required large quantities of hot water and/or steam for various applications traditionally used one or more boilers, which were located in a boiler house. It was from this one central energy source that the steam or hot water was distributed and recirculated, depending on demand. There is a trend today to install small package-type boilers or heat sources to supply dedicated sections of an installation. This reduces costs related to space required for boilers, amount of pipework and heat loss due to long runs of pipework. Reading Now read the resource by Puffet & Hossack, Plumbing services Volume 4, Mechanical services for further information. Specifically note the sections on: heat characteristics and measurement water heating and cooling systems steam heating systems. Systems, size, number and type of storage water heaters for commercial and industrial installations The systems include: cylinder system cylinder and tank system cylinder and calorifier system. To determine the type and how many storage water heaters a job is going to require you need to consider: heater application (what type of job, eg motel, canteen etc.) Refer to Rheem Hot Water Manual, section on Selection of water heaters for commercial use, sizing guide for heavy duty applications determine the type of application (eg snack bar) Commonwealth of Australia

44 peak demand (when is the most water required) determine the peak demand at which hot water is going to be required (eg one hour or spread over four hours) hot water requirements (how many litres over how many hours) calculate the amount of hot water required for this application. (eg 3.1 L per meal) heater type (gas or electric) determine the number and size of heaters that are going to satisfy the peak demand using selection tables. Selecting hot water heaters Hot water heaters are generally either gas or electric. To determine the differences between them for use in different circumstances please read the following sections from the Rheem Hot Water Manual. Reading 1 Gas heaters: Approximate volume of hot water available Refer to section 7 in the Rheem Hot Water Manual. Tables 7.3 to 7.7 in this section give the approximate hot water availability at 50 ºC rise for all heavy duty gas hot water heaters and 65 ºC rise for hot water heaters with thermostats capable of controlling the water temperature to 82 ºC. These tables cover different peak periods of one to eight hours. Reading 2 Electric heaters: Approximate volume of hot water available Refer to section 9 in the Rheem Hot Water Manual. Table 9.2 in this section shows a 50 ºC or 65 ºC rise in temperature from cold at approximately 17 ºC. You would need to determine whether the application warrants high temperature hot water at 65 ºC rise or as in most cases a rise of 50 ºC. High temperature hot water (82 ºC) is required for sanitising purposes, eg commercial kitchens. 42 Commonwealth of Australia 2015