CONSTRUCTION, PLUMBING AND SERVICE INTEGRATED FRAMEWORK TRAINING PACKAGE CPC08 CPCPWT3027A CONNECT IRRIGATION SYSTEMS FROM DRINKABLE WATER SUPPLY

Transcription

1 Commonwealth of Australia 2012

2 CONSTRUCTION, PLUMBING AND SERVICE INTEGRATED FRAMEWORK TRAINING PACKAGE CPC08 CPCPWT3027A CONNECT IRRIGATION SYSTEMS FROM DRINKABLE WATER SUPPLY LEARNING GUIDE ii Commonwealth of Australia 2015

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. This work was first published in 2004 with the assistance of funding provided by the Commonwealth Government through the Australian National Training Authority (ANTA). 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 2015 iii

4 Contents Unit Descriptor... 3 Element... 3 Performance Criteria... 3 Safety... 5 How will I be assessed?... 6 Are there any pre-requisites?... 6 What other resources will I need?... 6 Introduction... 6 Example... 7 Properties of water... 8 Pressure... 8 Static pressure... 8 Dynamic pressure (flow pressure)... 8 Flow rate... 9 Measuring water flow rates for a domestic irrigation... 9 Measuring the water flow using a bucket and stop watch... 9 Example... 9 Example Measuring the water flow using a dynamic flow testing device Types of irrigation systems Drinkable water supplies and protection measures Excavation processes and procedures Minimum cover in public areas Minimum cover in private property Procedures for jointing Copper compression joints Silver brazed joints Polyethylene compression joints PVC-U solvent cement joints Safety precautions for solvent cement weld procedures Test procedures iv Commonwealth of Australia 2015

5 Regulations Quality assurance Plan work activities Determining connection requirements Determining the connection size and valve size Determine the hazard rating Cross connection hazard ratings System types Protection required Individual protection Zone protection Selecting back flow prevention devices Backflow prevention devices Registered air gap (RAG) Registered break tank (RBT) Reduced pressure zone device (RPZD) Installation requirements for testable backflow prevention devices (RPZD) Pressure Vacuum Breaker Installation requirements for testable backflow prevention devices (PVB) Double check valve (DCV) Installation requirements for testable backflow prevention devices (DCV) Dual check valve (Dual CV) Atmospheric vacuum breaker (AVB) Installation requirements for non testable HCVB backflow prevention devices Selecting appropriate materials Ordering and checking the delivery Tools and equipment Connect and test the system Setting out Excavating the site Cutting into an existing metallic water service line Bonding straps Installing the water supply Restoring the water supply and testing the system Commonwealth of Australia 2015 v

6 Testing the system Clean Up Re-instating the ground surface Tools and equipment Worksheet Practical application Assessment checklist vi Commonwealth of Australia 2015

7 What is this resource about? Welcome to CPCPWT3027A Connect irrigation systems from drinkable water supply. This resource will help you gain the skills and knowledge necessary to demonstrate competence in this unit. How do I use this resource? This resource is divided into four main sections: A learning unit, which contains background information on CPCPWT3027A Connect irrigation system from drinkable water supply Worksheets, which prepare you for the practical application Practical application, which allows you to experience connecting irrigation systems from drinkable water supply Assessment materials, which help you demonstrate competency. To complete this unit of competence you will need to: read the information contained in the learning unit complete the worksheets as instructed have your answers checked by your trainer or supervisor work with your trainer or supervisor to practice connecting irrigation systems from drinkable water supply read the assessment checklist together with the assessment sheets complete the assessment. Learning Resources are not intended to be the only source of information nor are they intended to be an exhaustive form of instruction. Flexible delivery The Trainer or Supervisor may adapt and deliver this Learning Resource to suit people from diverse backgrounds to meet equity principles and conform to Legislative Policies. Commonwealth of Australia

8 What do I have to do? To demonstrate competence in this unit you will be required to show the level of skills and knowledge for each of the elements involved in connecting irrigation systems from drinkable water supply: Plan work activities Determine connection requirements Connect and test system Clean up. If you are unsure of the meaning of these elements you should read the performance criteria on the following page. 2 Commonwealth of Australia 2015

9 CPCPWT3027A Unit Descriptor Connect irrigation systems from drinking water supply This unit of competency specifies the outcomes required to connect irrigation and watering systems from a drinking water supply. It does not include the commissioning of backflow prevention devices or arrangements. Element Elements define the essential outcomes of a unit of competency. Performance Criteria Performance criteria describe the required performance needed to demonstrate achievement of the element. Where bold italicised text is used, further information is detailed in the required skills and knowledge and/or the range statement. Assessment of performance is to be consistent with the evidence guide. 1 Prepare for work 1.1 Plans and specifications are obtained 2 Identify installation requirements 1.2 Work health and safety (WHS) and environmental requirements associated with connecting irrigation systems from a drinking water supply are adhered to throughout the work 1.3 Quality assurance requirements are identified and adhered to according to workplace requirements 1.4 Tasks are planned and sequenced in conjunction with others involved in or affected by the work and statutory and regulatory authorities requirements 1.5 Tools and equipment for connecting irrigation systems, including personal protective equipment, are selected and checked for serviceability 1.6 Work area is prepared to support efficient connection of irrigation systems from a drinking water supply 2.1 Connection size and hazard rating are determined from plans, specification, relevant Australian standards and/or site inspection using relevant information 2.2 Valve is sized according to plans and specification 2.3 Back flow prevention devices are confirmed as being according to hazard rating 2.4 Materials and equipment are identified, ordered and collected according to workplace procedures 2.5 Materials and equipment are checked for compliance with relevant Australian standards, docket and order form, and for acceptable condition 2.6 Sustainability principles and concepts are observed when preparing for and undertaking work process 3 Connect and test system 3.1 Excavation is set out and made according to plans and specifications and undertaken with consideration given to Commonwealth of Australia

10 existing structures and services 3.2 Service pipe is isolated and cut to accommodate take off branch according to authorities' requirements 3.3 Back flow prevention device is fitted according to relevant Australian standards and manufacturer specifications 3.4 System is connected and flushed to required standard 3.5 Water supply is restored and system tested according to relevant Australian standards 3.6 Ground surface is restored 4 Clean up 4.1 Work area is cleared and materials disposed of, reused or recycled according to legislation, regulations, codes of practice and job specification Required knowledge 4.2 Tools and equipment are cleaned, checked, maintained and stored according to manufacturer recommendations and workplace procedures 4.3 Documentation is completed according to workplace requirements Required knowledge for this unit is: characteristics and application of different pipes and fittings, including fixing and joining techniques and methods drinking water supplies and protection measures implications of cross connections and air gaps job safety analysis (JSA) and safe work method statements (SWMS) process of connecting irrigation systems from a drinking water supply processes for accessing information and for calculating material requirements properties of water, including pressure and flow rates relevant statutory requirements related to connecting irrigation systems from a drinking water supply SI system of measurement Australian standards applicable to the connection use of test equipment and procedures various types of irrigation systems and types of materials used workplace and equipment safety requirements An up to date version of the Unit Descriptor may be located on the Australian Government web site training.gov.au ededdata=true&includesupersededdata=false&homepage=true&javascriptenabled=true&typealltra iningcomponents=true 4 Commonwealth of Australia 2015

11 Safety Workplace health and safety (WHS) requirements need to be observed in accordance with legislation. Revision of CPCPCM2043A Carry out WHS requirements, before commencing this unit is advisable. You need to know the WHS laws governing your job. Revise CPCPCM2043A Carry out WHS requirements before commencing this unit. In any work situation you can reduce the risk of injury to yourself and others by using appropriate personal protective equipment (PPE). The types of PPE that you will need include: Overalls used for the protection of the installer when working in different conditions Boots it is recommended that soft soled footwear is worn while working on roofs, as deep grooved footwear pick up small stones and debris that might damage or scratch the roof sheets Safety glasses or goggles to protect the eyes from injury when cutting the sheets with a power saw Ear plugs or muffs to protect the installer s hearing form excessive noise Dust masks or respirators to protect the user from breathing in dust or fine particles when cutting the sheets with a power saw Gloves, for the protection of the installer s hands when working with different types of pipes, tools and equipment. Commonwealth of Australia

12 How will I be assessed? Your trainer or supervisor will decide with you how you will be assessed. Your assessment activity may include completion of the participant worksheet and practical task selected by your trainer or supervisor. Your assessment should allow you to demonstrate all the skills and knowledge required to connect irrigation and watering systems from the drinkable water supply. This unit may be assessed in conjunction with other units of competence. Your trainer or supervisor will tell you if you are to be assessed this way. Are there any pre-requisites? Prior to commencing CPCPWT3027A Connect irrigation system from drinkable water supply you must have successfully completed the following pre-requisites. CPCPCM2043A Carry out WHS requirements It is also recommended that prior to commencing CPCPWT3027A Connect irrigation system from drinkable water supply you should have successfully completed the following competencies. Nil. Project work may also group pre-requisite and or co-requisite competencies together to carry out such projects. It is recommended that the following competencies are grouped with this unit of competency: Nil. What other resources will I need? To assist you the following resources have been suggested and should be available to you to do this competency. Texts AS/NZ3500 Plumbing and drainage. Plumbing code of Australia. State and Territory regulations may override this Learning Guide. Web sites Video/audio cassettes Introduction In this unit you will look at connecting irrigation and watering systems from the drinkable water supply. Whenever a connection is made to a potable water supply the integrity of that potable water supply must be maintained at all times. 6 Commonwealth of Australia 2015

13 Irrigation systems may range from a simple, manually controlled drip system resting on the ground to a computer managed, multi-zoned, pop-up rotor system. Whichever system is installed there is always the distinct possibility of contamination of the water supply happening if the system does not have the correct backflow prevention device installed. Contamination of the water supply can easily happen if a backflow valve has not been installed and the supply water pressure fails during the sprinkler operation period. When the supply pressure fails a negative pressure may form in the supply main. This could suck contaminated water back into the main supply through the sprinkler system. Example An example of this may be as follows. The water supply to a pop-up system installed in a lawn area fails during the operation period. The lawn area has several sprinkler heads installed and one of these has a puddle formed over it when the head is retracted. If the supply failed during operation and a backflow valve has not been installed this water could be sucked back to, and contaminate, the water main supply line. When the water supply is reinstated this contaminated water will be carried downstream. Thus any downstream users will be supplied with dirty water. This demonstrates the need for backflow protection on all irrigation systems at all times. This unit will look at the types of irrigation systems that can be installed and the types of backflow protection required for each system type. Before you can connect irrigation and watering systems there are several issues that you must know, including: properties of water including pressure and flow rates various types of irrigation systems and the types of materials used drinkable water supplies and protection measures excavation processes and procedures Test procedures to check for leaks, pressure levels and venting requirements. Commonwealth of Australia

14 Properties of water If you are using water from a source other than a reticulated main you will need to have the water analysed to determine its suitability for irrigation purposes. The water salinity (salt content) may be too high for the plants you intend to irrigate. Water from a reticulated supply will usually be suitable for irrigation purposes. Wherever the water supply is from you will need to determine the supply properties of the water. The water supply properties that affect irrigation are as follows. Pressure The units of pressure are Pascals (abbreviated to Pa). However a Pascal is very small so the usual pressure units used to measure water pressure are the kilopascal (kpa). One kilopascal (kpa) is equal to 1000 Pascals (Pa). Other pressure units by manufacturers include the following. Other pressure units Conversion factor for KPa. Pounds per square inch (psi) X 6.89 Bars (b) X 100 Converting 20 psi to kpa Converting 1.38 Bars to kpa 20 psi x 6.89 = 138 kpa 1.38 Bars x 100 = 138 kpa Supply water pressure can be measured in two ways: static pressure dynamic pressure (flow pressure) Static pressure This is the pressure available when there is no water flowing. However, this pressure does not indicate there will be enough water flow for the irrigation system. Dynamic pressure (flow pressure) This is the pressure available when the water is flowing at the required flow rate. This pressure will indicate if you have enough pressure and water flow combined to supply the irrigation system requirements. 8 Commonwealth of Australia 2015

15 Flow rate The unit of volume flow rate is cubic metres per second (m 3 /s). This is a very large volume of water so the usual flow rate unit used is the litre per second (L/s). This unit has been derived from the cubic metre per second as shown below. One cubic metre per second (m 3 /s) is equal to 1000 litres per second (L/s). Other units of flow rate used by irrigation manufacturers include the following. Other units of flow rate Conversion factor for I/S Cubic metre per hour (m 3 /h) 3.6 = L/s Litres per minute (l/min) 60 = L/s Table 2 An example of the conversion process. Converting 7.0 m 3 /h to L/s Converting 117 L/min to L/s 7.0 m 3 /h 3.6 = 1.95 L/s 117 L/min 60 = 1.95 L/s Measuring water flow rates for a domestic irrigation If a simple spray system is to be connected to a reticulated water supply, opening a tap and timing how long it takes to fill a bucket is adequate to measure water flow rates. However, for pumps and systems that require set pressures to operate, you will need to connect a dynamic pressure/flow measuring device which measures the dynamic pressure while you time how long it takes to fill a bucket. Measuring the water flow using a bucket and stop watch When you measure the water flow rate using a stop watch and bucket (see figure below) you will have a final reading that tells you how many seconds it takes to fill a bucket that you know holds a set amount of water. The results of this test will need to be converted to litres per second. Example You need to determine the water flow rate from the water main at a clients property. 1. Select a tap close to the water meter or near to the point you are going to tap the irrigation system into the clients water supply. 2. Select a large bucket (25 litres would be best). Commonwealth of Australia

16 3. Open the tap fully. 4. Push the bucket under the tap and start your stop watch at the same time. 5. Stop the timer when the bucket is full but not overflowing. 6. You will have a reading of how many seconds it takes to fill a 25 litre bucket from that tap. Example It takes 22 seconds to fill a 25 litre bucket. This must be converted to litres per second. Using a stop watch to time the filling of a bucket The following table shows the information you should record during a test. Client details: Mr Example Time of day Location of tap 2.29 pm Front yard near meter a. Bucket capacity 25 litres b. Time to fill bucket 22 seconds a b = Litres per second L/s Divide the number of litres (25 L) by the number of seconds (22 s) to get the number of litres per second (1.14 L/s). 10 Commonwealth of Australia 2015

17 Measuring the water flow using a dynamic flow testing device A dynamic flow testing device consists of a length of tube that has a 20 mm nut and tail on one end (so you can screw it onto a bibcock). On the other end of the pipe there is a full bore ball valve with an orifice or nozzle and toward the centre of the pipe a pressure gauge is connected. You will need to follow these steps to measure the dynamic water flow. 1. Connect the tester to the tap and open tap fully, close the ball valve and record the static pressure registering on the gauge. 2. Open the ball valve fully. With the water flowing full bore note the dynamic pressure reading on the gauge. 3. Push a bucket under the water stream and start timing. 4. Stop the timer when the bucket is full and remove the bucket. 5. Read the dynamic pressure on the gauge once again. If it is not the same as when you started you will need to repeat the steps above. Timing the filling of a bucket and measuring the dynamic pressure Commonwealth of Australia

18 Client details: Time of day am/pm Location of tap Static pressure Dynamic pressure at start of test Dynamic pressure at end of test kpa kpa kpa a. Bucket capacity litres b. Time to fill bucket seconds a b = Litres per second L/s The following table shows how the flow rate and dynamic pressure may be recorded. The results of this test will tell you the volume (L/s) of water that can be delivered to the irrigation system at a given pressure. An example of the readings obtained together with the flow rate and dynamic pressure from this test is shown in the following table. This information is required when you are calculating the pressure losses through the piping for the irrigation system. Client details: Mr Example Time of day Location of tap Static pressure (no flow) Dynamic pressure at start of test (full flow) Dynamic pressure at end of test (full flow) am Next to meter 850 kpa 250 kpa 250 kpa a. Bucket capacity 25 litres b. Time to fill bucket 17 seconds a b = Litres per second 1.47 L/s 12 Commonwealth of Australia 2015

19 Types of irrigation systems There are various types of irrigation systems that may be installed and connected to the reticulated town water supply. You will need to select the correct backflow prevention device for the system being installed. This will involve identifying the system type and selecting a backflow prevention device for the system and then installing the backflow device in the correct manner. Australian Standard AS/NZS Section 7 Irrigation and lawn water systems, classifies irrigation systems into four categories. These are Types A, B, C and D. Look at section 7 of AS/NZS carefully and note the possible system layouts and the backflow prevention devices required to be installed. Type A systems do not require a back flow prevention device to be installed. They have permanently open outlets and piping mounted more than 150 mm above the finished ground level, that are not subject to ponding or back pressure. They do not have injection systems connected to them. Type A irrigation systems Commonwealth of Australia

20 Type B systems as shown below. These require a non-testable, backflow prevention device to be installed. Type B systems are any irrigation systems in a domestic or residential situation that are installed closer than 150 mm to the finished ground level and that do not have injection systems connected to them. The following are 2 examples only: Type B irrigation system with a hose connection vacuum breaker Type B irrigation system with an atmospheric vacuum breaker 14 Commonwealth of Australia 2015

21 Type C systems require a testable backflow prevention device such as a double check valve assembly to be installed. Type C systems are irrigation systems used in locations other than domestic or residential locations with piping and outlets lower than 150 mm from the finished ground level and that do not have injection systems connected to them. The following is one example only: Type C irrigation system requiring a testable backflow prevention device Type D systems require a testable backflow prevention device such as a reduced pressure zone device to be installed. Type D systems require the maximum backflow protection because they are irrigation systems that have chemicals injected or siphoned into the pipes supplying the emitters. Type D irrigation system which has chemicals injected or siphoned into the pipes. Worksheet Now go to the Worksheet and answer Questions 1 6. Commonwealth of Australia

22 Drinkable water supplies and protection measures A drinkable, or potable water supply is water suitable for human consumption. Reticulated town main potable water supplies are supplied under pressure to each property. This makes it convenient to use for purposes other than human consumption, such as irrigation. It is for this reason that it must be protected from contamination at all times by selecting and installing the correct backflow protection device to each system. The types of irrigation system and the backflow protection device each requires is discussed earlier in these notes. Excavation processes and procedures You will need to carry out excavation work using appropriate procedures. This will involve locating and exposing the existing underground services such as: power cables communications cables gas lines sewer storm water pipes non drinking water service The initial site inspection and subsequent investigations should have identified the locations of these services. The existing water service must be carefully exposed by using a shovel. In the unlikely event of the water service being at a depth greater than 1.5 metres when working on any trenching operation, you must observe the regulations and WHS requirements in accordance with each State or Territory s legislation. A number of States no longer have regulations covering trenching operations and rely on the WHS act and codes of practice to ensure the tasks involved in trenching operations are performed correctly and safely. Note Check with your trainer or supervisor the requirements relating to local regulations, codes or practice and WHS requirements within your state. It is the Employer s responsibility under the WHS Acts & WorkCover Acts to: make sure they maintain, as far as practicable, a safe working environment that is without risks to health provide adequate training to employees. 16 Commonwealth of Australia 2015

23 Note Self employed people are treated as employers under the WHS Act. It is your responsibility under the WHS Act as an employee: to perform your work in accordance with safety standards and codes of practice to make sure you take all necessary care to protect yourself and others that may be affected by your work. Remember each job must be treated as an individual problem. You must take into account the variable conditions, existing or potential, on the job. You should consider these factors which contribute to the stability of the excavation. These are: type of ground possibility of flooding depth and shape of excavation size and location of spoil heap or other heavy weights, eg machinery buildings close to excavation vibration from traffic or other sources ground water conditions adjacent drains and services. The types of ground support systems you may need to use can include: collar sets (or box sets as they are sometimes called) close timber sheeting soldier sets segmental sections trench shields. The following diagram illustrates a collar or box set which is the type of support system usually used for trenches with a depth of 1.5 metres or less. Commonwealth of Australia

24 A collar or box set ground support system Once you have exposed the water service, enlarge the excavation (making sure the trench is adequately supported) to allow you to comfortably make the connection for the irrigation system. The depth of the water service will vary from property to property. However, the following tables indicate the minimum depth of cover over the existing water service pipes for public and private land. Minimum cover in public areas Location Minimum cover measure below ground surface level Unpaved Paved or road surfaces Solid rock 450 mm 450 mm 300 mm Minimum cover in private property Location Subject to vehicular traffic Under houses or concrete slabs All other locations Minimum cover measured below ground surface level 300 mm 75 mm 225mm 18 Commonwealth of Australia 2015

25 The jointing methods and procedures will depend on the pipe material used on the domestic water service line. AS/NZS specifies the materials that are approved for use on water services. Generally the water service after the meter will be copper, unplasticised polyvinylchloride (PVC-U) or polyethylene (PE). Material Copper Jointing methods Compression fittings are available in various forms, i.e. flared, olive and croxed Silver solder PE (Polyethylene) Compression fittings PVC-U (Unplasticised polyvinylchloride) Solvent cement Procedures for jointing Listed below are several methods of jointing various types of materials. Copper compression joints Tube ends must be cut square and de-burred. If flaring a tube remember to slip the nut onto the pipe before you flare it. Flaring, swaging and croxing tools must be well maintained and free from damage. Do not twist or distort the tube by over-tightening. Tube must not be crimped or grooved. Silver brazed joints Tube ends must be square, de-burred and thoroughly clean. Fully engage the tube into the fitting or expanded end of mating tube. Support joint well before applying heat. Apply heat in a uniform manner to the tube and joint area until just cherry red. Apply silver solder onto the shoulder of the fitting. It should melt on contact and flow by capillary action around the joint. Maintain a cherry red colour until joint penetration is complete. Avoid overheating and forming globules of filler inside and outside the joint. When the joint is complete allow it to cool in air until the silver solder solidifies. The silver brazing filler metal must contain a minimum of 1.8% silver and maximum 0.05% cadmium as specified in AS/NZS Commonwealth of Australia

26 Flux is not necessary for copper-to-copper joints when a silver-phosphorus-copper filler metal is used but must be used for brass fittings and pipes. When flux is used, it should be applied uniformly and sparingly. Polyethylene compression joints Unscrew the fitting so that three or four threads are showing. Cut the pipe to the required length and de-burr the end. Insert the pipe into the fitting to the correct depth. Make sure the pipe has been pushed past the o-ring seal. Tighten the nut. To disassemble simply unscrew the nut and pull the pipe from fitting. This procedure may not suit all polyethylene fittings. Check with the manufacturer of the fittings you are using to obtain the correct procedure. The manufacturer may have a web site showing the correct fitting procedures for their pipe fittings. Visit the Vinidex site at and view their instructions. PVC-U solvent cement joints The following steps are a précis of the information available at the Vinidex web site address Do not work with hot pipes or on hot windy days without protecting pipes. Keep lids on solvent cement bottles or cans to minimise evaporation. Use solvent cements within twelve months of the date stamped on the bottom of the bottle or can. If the solvent cement has become so thick that it does not flow easily, discard it. Cut the pipe spigot square and de-burr. Check that the pipe and fitting are correctly aligned. Clearly mark the spigot depth. Dry fit the joint. Clean and soften the surface using a lint free cotton cloth dipped in priming fluid. Apply a thin, uniform coat of solvent cement to the socket first and then the spigot. Assemble and hold for at least 30 seconds without movement. Do not disturb the joint for at least five minutes. Do not pressure test the joint for at least 24 hours. Short cuts will result in poor joints that are likely to fail. 20 Commonwealth of Australia 2015

27 Safety precautions for solvent cement weld procedures Solvent cement and priming fluids are highly flammable. In the event of fire, smother with sand or earth or use a suitable fire extinguisher. Store solvent cements and priming fluid in a cool place away from heat, flames and sparks. Make sure can lids are sealed tightly when not in use. Do not add any other ingredients or solvents to these products. Do not use solvent cements or priming fluid in confined spaces without adequate ventilation, or near open flames or sparks. Do not smoke while using these products. If spilt on skin, wash off with soap and water. If poisoning occurs, consult a doctor or Poisons Information Centre. Test procedures Test procedures need to be conducted to ensure that the installation operates effectively. These tests include: pressure and leak testing on the mains side of the backflow prevention device, according to the requirements of AS/NZS testing of the backflow device to ensure it performs correctly and as designed Note: If a testable backflow device it must be tested by an approved person. flow and pressure tests of the completed installation to ensure the system operates correctly. Regulations When working on any task you must observe the regulations and the WHS requirements in accordance with the State or Territory legislation. Selection and installation of backflow prevention devices must be undertaken in accordance with AS/NZS Water service. The purpose of these regulations is to protect all participating parties and to ensure that safe practices are maintained throughout the entire work procedure. Failure to follow WHS requirements and other legislation will leave you open to prosecution, which in the advent of a fatality on site or due to a faulty installation, could lead to a charge of manslaughter being applied. Commonwealth of Australia

28 Quality assurance Most companies these days have a policy for assuring quality to the customer. This policy is designed to control the processes used within the company, record keeping, quality of materials used and the way the work is done. You need to be aware of your company s particular quality assurance requirements. A number of quality assurance issues are dealt with in the next section, Plan work activities. Workplace operations and procedures: follow company procedures for safe working follow company procedures for record keeping. Quality of material: materials used in the installation must comply with the plans or specifications materials used in the installation must comply with any appropriate Australian Standards that apply material must be checked at delivery for damage caused during transport. Control of handling procedures: use correct manual handling techniques select and use appropriate load shifting equipment. Use and maintenance of equipment: select and use appropriate tools for each part of the job regularly inspect tools for wear or damage tag faulty equipment and notify your supervisor. Attention to specifications: use only specified materials and procedures for the installation. 22 Commonwealth of Australia 2015

29 Plan work activities Before you begin the connection of the irrigation or watering system you need to obtain the plans and or specifications from the job supervisor. Gathering information about the job will help you make informed decisions about the nature of the job and how to plan and sequence the entire process. Before beginning any work you may need to obtain work notices and submit them to the relevant authorities. The table below shows information sources you will use and the type of information each source can provide. Source of information Authorities Plans or specifications Company s quality assurance Regulatory requirements Site inspection Others involved with the work The information provided Location of property services, eg a power, communications, gas and water. Location, sizes and layout of irrigation pipe work and location of other services. Workplace operations and procedures: quality of material control of handling procedures use and maintenance of equipment attention to specifications. Registration and or licensing of plumbing workers. Check local authority requirements for paperwork, certificates etc relating to the installation. Verification of plans and access for work. Timelines for work completion stages. Note There are many other tradespeople that may require access to the site. You should plan the tasks with all these tradespeople involved or affected by the work. Your company may have procedures regarding this process. Commonwealth of Australia

30 Determining connection requirements You are now ready to determine connection and valve sizes, check the hazard rating and select back flow prevention devices. Any materials you require should be ordered and checked on delivery, and tools and equipment (including PPE) should be organised. Determining the connection size and valve size Using the job specification or a site visit will allow you to determine the connection size to the water supply and the valve size. Most domestic water services are in either 20 mm or 25 mm copper, PVC-U or PE. You will need to verify the pipe material and size on site by exposing the water service after the meter and measuring the diameter of the pipe. Determine the hazard rating The hazard rating of the installation may be determined in accordance withas/nzs Section 4, Section 7 and table 4.1 The hazard rating and subsequent selection of a backflow prevention device for an irrigation system depends on the: cross connection hazard system types protection required. Cross connection hazard ratings Rating High hazard Medium hazard Low hazard Condition Any condition, device or practice which is connected to the potable water supply and has the potential to cause death. Any condition, device or practice which is connected to the potable water supply and has the potential to endanger health. Any condition, device or practice which is connected to the potable water supply and has the potential to be a nuisance but not endanger health or cause injury. 24 Commonwealth of Australia 2015

31 System types As mentioned previously in this document, irrigation systems are classified into four types. These are detailed together with the appropriate backflow prevention device requirements, in the following table. System type Description Backflow prevention device required Type A Type B Type C Type D Has a permanently open outlet and piping mounted more than 150 mm above the finished ground level that is not subject to ponding or back pressure and does not have injection systems connected. Any irrigation system in a domestic or residential situation that is installed closer than 150 mm to the finished ground level and that does not have injection systems connected. Irrigation system used in locations other than domestic or residential with piping and outlets lower than 150 mm from the finished ground level and does not have injection systems connected. Irrigation systems that have chemicals injected or siphoned into the pipes supplying the emitters. Does not require a back flow prevention device to be installed. Requires a non-testable backflow prevention device such as one of the following, to be installed. Atmospheric vacuum breaker. Hose connection vacuum breaker. Dual check valve. Requires a testable backflow prevention device, such as one of the following, to be installed. Double check valve assembly. Pressure vacuum break. Requires a testable backflow prevention device, such as one of the following, to be installed. Reduced pressure zone device. Registered break tank. Commonwealth of Australia

32 Protection required Individual protection Hazard ratings and a selection of backflow prevention devices for backflow prevention protection at individual fixtures, appliances or apparatus. Agricultural and horticultural Form of cross connection Hazard rating Backflow prevention device required Fertilizer, herbicides, nematicides, insecticides and weedicides injected into an irrigator. (seeas/nzs Section 7, Type D) Hose attachment outlets Hose taps located within 18 m of a Type C irrigation system High Medium Refer AS/NZS Suitability of devices RBT (Registered Break Tank) or RPZD (Reduced Pressure Zone Device) Refer AS/NZS Suitability of devices Testable device Double check valve. 26 Commonwealth of Australia 2015

33 Zone protection Hazard ratings and a selection of backflow prevention devices for backflow prevention protection at the connection to specified sections of a water supply system within a building or facility. Agricultural and horticultural Form of cross connection Hazard rating Backflow prevention device required Irrigation systems injected with fertilizer, herbicides, nematicides, insecticides (seeas/nzs Section 7, Type D) Irrigation systems (seeas/nzs Section 7, Type C) Irrigation systems (seeas/nzs Section 7, Type B) High Medium Low Refer AS/NZS Suitability of devices Registered break tank (RBT) Or Reduced pressure zone device (RPZD) Refer AS/NZS table 4.1 Suitability of devices Testable device Refer AS/NZS table 4.1 Suitability of devices Non testable device Selecting back flow prevention devices The hazard rating will determine the backflow prevention devices that will be needed for the installation. To select the appropriate backflow prevention device for the hazard rating you will need to: identify the irrigation system type from the System types table identify the hazard rating of the irrigation system from the protection tables select the valve most appropriate for the installation. The valve choice will depend on the fall of the land, whether it is falling away from the connection point or toward the connection point. If the land falls away from the connection point and it is a Type C system the choice of backflow device could be a pressure type vacuum breaker. (This is provided the pressure vacuum breaker is at least 300 mm above the highest emitter.) Commonwealth of Australia

34 If the land rises from the connection point, that is, the irrigation system is above the connection point; a double check valve assembly could be selected. Backflow prevention devices Registered air gap (RAG) An air gap in a storage tank or the air over a fixture, vat or drum of non potable liquid. Registered break tank (RBT) A storage tank incorporating an air gap specifically designed for the purpose of backflow protection. Reduced pressure zone device (RPZD) There are two types of reduced pressure zone devices (RPZD) and they offer the highest protection available in a mechanical device. They are: in a normally closed form (independent check valve) in a normally open form (diaphragm). Reduced pressure zone device Installation requirements for testable backflow prevention devices (RPZD) Valves must not be: buried or mounted in a pit hidden so water venting from relief port cannot been seen located in areas likely to flood or pond located where contaminated air can enter the piping via the relief valve port installed if a maintenance program for device registration and certification is not available. Valves must have: resilient seated isolating valves fitted before and after the valve and strainer assembly line strainers installed relief drain outlet at least 300 mm above surrounding surface protection from freezing. 28 Commonwealth of Australia 2015

35 Pressure Vacuum Breaker These are used on medium hazard installations such as Type C irrigation systems, where the device is under continuous pressure. PVB valves stop back siphonage occurring, they allow air into the pipe via the atmospheric port preventing a vacuum from forming. They discharge any water backflow to the atmosphere and protects against back siphonage only. Pressure vacuum breaker Installation requirements for testable backflow prevention devices (PVB) Valves must not be: buried or mounted in a pit hidden so water venting from relief port cannot been seen located in areas likely to flood or pond located where contaminated air can enter the piping via the relief valve port installed if a maintenance program for device registration and certification is not available. Valves must have: - resilient seated isolating valves fitted before and after the valve and strainer assembly - line strainers installed - their mounting position at least 300 mm above the highest outlet - protection from freezing. Double check valve (DCV) Double check valves are used on medium hazard installations such as Type C irrigation systems, where the device is under continuous pressure and back pressure. They consist of two spring loaded check valves that require a pressure of 7 kpa pressure difference to open. If a backflow situation occurs the two valves will close preventing reverse flow and protects against back pressure and back siphonage. Commonwealth of Australia

36 Double check valve (DCV) Installation requirements for testable backflow prevention devices (DCV) Valves must not be: buried or mounted in a pit located in areas likely to flood or pond installed if a maintenance program for device registration and certification is not available. Valves must have: resilient seated isolating valves fitted before and after the valve and strainer assembly line strainers installed protection from freezing. Dual check valve (Dual CV) These are used on low hazard installations such as Type B or C irrigation systems where the device is under continuous pressure. They consist of two spring loaded check valves that require a pressure of 7 kpa pressure difference to open. If a backflow situation occurs the two valves will close preventing reverse flow. Dual check valve 30 Commonwealth of Australia 2015

37 Atmospheric vacuum breaker (AVB) These are used on low hazard installations such as Type B or C irrigation systems to stop back siphonage occurring. They allow air into the pipe upstream of the device preventing a vacuum from forming. These devices cannot be used under continuous pressure situations. Atmospheric vacuum breaker Installation requirements for non testable backflow prevention devices (Dual CV, DCAP, AVB) Valves must not be: buried or mounted in a pit hidden so water venting from relief port cannot been seen located in areas likely to flood or pond located where contaminated air can enter the piping via the relief valve port continuously subjected to pressure for more than 12 hours per day (AVB). Commonwealth of Australia

38 Valves must have: resilient seated isolating valves fitted before and after the valve and strainer assembly line strainers installed relief drain outlet at least 300 mm above surrounding surface (DCAP) mounted at least 150 mm above highest emitter (AVB) protection from freezing operation checked every two years. Hose connection vacuum breaker (HCVB) These are used on hose bib taps; they prevent back siphonage in applications where hoses are connected. Hose connection vacuum breaker Installation requirements for non testable HCVB backflow prevention devices Valves must not be: continuously under pressure for more than 12 hours per day installed upstream of the tap located where contaminated air can enter the piping via the relief valve port. Valves must have: 450 mm clearance between highest emitter and HCVB vent port ventilation at all times operation checked every two years. Selecting appropriate materials Using the plans or specifications, or a site inspection, will allow you to decide on which materials and components are needed for the job. You will need to calculate the quantity and types of materials to order and ensure that they comply withas/nzs and the job specification. 32 Commonwealth of Australia 2015

39 Ordering and checking the delivery Once the materials and quantities have been determined they need to be ordered. Pipe fitting quantities should be ordered exactly as from the plan and materials take off sheets. Before ordering pipe and fittings, double check your list and plan to ensure nothing has been left off. Remember only approved materials, fittings and products as specified in AS/NZS may be used on the water service. When ordering, make sure only approved type pipe and materials are to be used. (As per AS/NZ3500.1) The order is made up using the materials take off list that was produced at the design stage of the project. On arrival you need to check the materials to ensure that they are of the standard required and have been delivered in acceptable condition. Check the materials to ensure that they are: correct for the intended installation of the standard required in acceptable condition as ordered and nothing is missing. Worksheet Now go to the Worksheet and answer Questions 1 8. Tools and equipment To work efficiently and safely you will need to have and use various PPE to protect yourself, including: overalls safety boots gloves safety glasses welding glasses hardhat fluorescent orange (DAYGLO) jacket, when working on or near roads ear plugs or ear muffs dust mask or respirator. Commonwealth of Australia

40 You will need a range of hand and power tools and other equipment. The following is a list of tools and equipment you may require to complete the work. This list is not meant to be all-inclusive! Adjustable spanners and wrench. Flaring block and pin. Claw hammer. Hack saw. Screwdrivers. Tap measure. Multigrips. Cold chisel. Oxy/acetylene welding equipment and PPE. Shovel. Pick. Crowbar. Wheelbarrow. Trench shoring equipment. 34 Commonwealth of Australia 2015

41 Connect and test the system Now that you have all the tools, equipment, PPE and materials you need, you can begin to connect the irrigation system. The set out must not damage or interfere with any existing structure or service such as electrical connections. You must excavate to the set out safely and fit the irrigation system to specifications and any regulatory authority requirements. The system can then be flushed and water supply restored. Setting out Pipe lines and excavation areas need to be set out by carefully cross referencing the details shown on the site plan and system plan. The locations of existing services and pipes need to be carefully pegged out and marked using fluorescent spray paint before laying out new work. Irrigation pipes, trenches etc can be set out on the ground using string lines and their positions marked using lime dust or chalk powder. Excavating the site You will need to carry out excavation work using appropriate procedures. This will involve: providing for the protection of yourself, other workers, and the general public by erecting warning signs, barricades, and planks etc, around the area in which the excavation is to be carried out. If the excavation is to be left overnight the excavation will require lights locating and exposing by hand using a shovel, the water service and any other underground services such as power cables, communications cables, gas lines, sewer and storm water pipes. The initial site inspection and subsequent investigations should have identified the locations of these services. Once these services have been exposed you can, if necessary, continue excavating using mechanical equipment. Cutting into an existing metallic water service line Many factors can adversely affect the standard and condition of an electrical installation. This can result in a stray electrical current passing through water pipes or other metallic components and structures. This stray electrical current can kill you if you cut the pipe breaking the electrical circuit and then bridge the broken circuit with your body. Before cutting through an existing metallic water service pipe, you need to make sure there is no stray electrical current by using a neon tester. Commonwealth of Australia