Mobile water supply testing apparatus and method of conducting installation integrity testing on mains water supply pipework

Abstract

A mobile testing device 2 is provided for conducting installation integrity testing on mains water supply pipework (1, figure 1). The device comprises a first fluid holding tank 5 with a pump 6 and a

Description

The present invention relates to a method of testing the integrity of pipework installed for the purposes of mains water supply and testing apparatus for use in such testing. Background of the Invention A supply of clean water is one of principal utilities that must be installed in any construction project, whether it be a commercial development, such as a factory or a retail outlet, or a residential development with one or more dwellings. Traditionally clean water is provided to a locale via a mains water supply, which comprises a water main that supplies a plurality of service lines which deliver the clean water to individual buildings / dwellings. Both the water main and the service lines take the form of pipework that is installed below ground level. The below-ground placement of the water delivering pipework requires that their installation is typically carried out at a very early stage of a development so that the water supply network is established before the above-ground construction (e.g., buildings and roads) commences. In the event that faults, in the form of leaks for example, are discovered after the above-ground construction stage this can necessitate considerable remedial works that can be both costly and time consuming. In order to negate this possibility, post installation pressure testing of mains water supply pipework is carried out to identify faults before the pipework is completely buried so that remedial action can be taken in a timely manner while the pipework is still readily accessible. At present, this pressure testing is carried out using an ad hoc collection of pumps and pressure gauges to deliver fluid into the pipework under pressure and then monitor for pressure losses, which might be indicative of a leak. Most newly installed mains water supply pipework is formed from materials that exhibit visco-elastic behaviour, such as polyethylene and polypropylene. Visco-elastic stress (sometimes referred to as ‘creep’) can affect the pressure measurements as the pipework will expand and contract as a result of changes in pressure and this will affect the pressure readings. If the pipe expands then there will be an associated reduction in pressure due to an increase in internal volume of the pipe. As such, additional testing stages may be employed to account for the effects of creep when pipework is subject to pressurised fluid testing. This typically requires the use of further equipment which increases the complexity of the testing and with it a risk of user error that can lead to poor test results and possibly even safety hazards due to the high pressure conditions involved in the testing which can be as high as 16bar (235psi). Summary of the Invention The present invention provides a mobile testing device for conducting installation integrity testing on mains water supply pipework in accordance with claim 1 and a method of testing the installation integrity of a section of mains water supply pipework in accordance with claim 11. Both the mobile testing device and the method are considered particularly suitable for testing pipework that is formed from materials that exhibit visco-elastic behaviour, such as polyethylene and polypropylene. In a first aspect the present invention provides a mobile testing device for conducting installation integrity testing on mains water supply pipework, said device comprising: a first fluid holding tank with a pump and a second fluid holding tank with a volumetric gauge, wherein the two tanks are arranged in a configuration that allows fluid to return from the second tank to the first tank via an actuatable valve; wherein the first fluid holding tank and the second fluid holding tank are connected in fluid communication with a pipework engagement interface via conduit means that comprise pressure sensing means and a two-way valve assembly, said pipework engagement interface being configured to form a fluid-tight seal with a section of main water supply pipework; and wherein said two-way valve assembly is actuatable to switch between two alternative fluid flow path configurations, in which: a) the first tank, the pipework engagement interface and pressure sensing means are connected in a first fluid flow path configuration; and b) the second tank, the pipework engagement interface and pressure sensing means are connected in the second fluid flow path configuration. The mobile testing device of the present invention can be employed to deliver reliable and repeatable pressure testing for main water supply pipework that accounts for the effects of visco-elastic behaviour in the pipework by allowing for the device to be switched between different configurations quickly and safely without having to manually detach one component and reattach another component. Preferably the device may further comprise computer operated control means that are programmed to actuate the two-way valve assembly to facilitate the flow of fluid through each of the available fluid flow path configurations. Further preferably the control means are also programmed to operate the pump. It is envisaged that employing a testing programme that is executed by a computer operated control means further reduces the potential for variations in the testing procedure that might occur when the steps of the method are carried out manually. This further ensures reproducibility of the testing procedure across a range of pipework installations, which allows for the collection of comparable data. Preferably the computer operated control means are programmed to actuate the valve between the first and second fluid storage tanks so that fluid can return from the second tank to the first tank. Whilst it is envisaged that the fluid can be actively pumped from the second tank to the first tank, in a preferred arrangement the second tank is arranged above the first tank so as to facilitate the fluid return under the force of gravity. The provision of an actuatable fluid return pathway, from the second fluid storage tank back to the first fluid storage tank, enables the re-use of the testing fluid, which makes the testing apparatus much more water efficient. This is considered particularly beneficial when testing is carried out in locations remote from fresh supplies of water. Preferably the conduit means may further comprise in-line filtration and / or sterilization means. The provision of in-line filtration and / or sterilization means help to maintain the quality of the testing fluid employed by the mobile testing device, which in turn allows the same fluid to be used multiple times rather that requiring fresh fluid for every test. Cleaning the fluid also reduces the potential for contaminating mains water pipework during testing. Preferably the computer operated control means may be configured to collect data from the pressure sensing means, interpret that data for use by the device for control and the testing protocol, and then store and / or export such data for confirmation that the pipework is suitable for use. Preferably the device may further comprise temperature sensing means configured to monitor the temperature of fluid entering and leaving the device via the pipework engagement interface. It is envisaged that monitoring the temperature of the fluid as it enters / leaves the device ensures that the testing is conducted within acceptable parameters. For instance, it is generally considered that the temperature within the pipework should not exceed 25°C during pressure testing. Monitoring the temperature of the fluid leaving the device can be used to ensure that the fluid entering the pipework is of an acceptable temperature, whilst monitoring the temperature of the fluid entering the device can be provide an indication of the temperature within the pipework. In situations where the temperature being measured is too high, the control means, which is operably connected to the temperature sensing means, can be configured to pause the testing procedure. Preferably the computer operated control means may be configured to receive information from the pressure sensing means and the volumetric gauge and use such to dictate the operation of the pump and the actuation of the two-way valve assembly. Once again, this will help to increase the level of autonomy exhibited by the device, which ensures reproducibility of the testing procedure across a range of pipework installations. Preferably the first fluid storage tank may be provided with a fluid inlet that is configured to facilitate a fluid connection with a supplementary water source. In this way the the first storage tank can be topped up when the volume of test fluid required for the section of pipework exceeds the capacity of the tank. Preferably the device may be mounted on a wheeled base which may have an enclosure for security and protection of the apparatus. This enables the device to be manoeuvred into position close to the pipework that is to be tested. A second aspect of the present invention provides a method of testing the installation integrity of a section of mains water supply pipework, said method comprising: a) connecting the mobile device of the present invention to said section of pipework via the pipework engagement interface to form a test system; b) actuating the two-way valve assembly to set up a first flow path configuration, in which a first fluid holding tank and the section of pipework are in fluid communication, and then pumping test fluid from the first tank into the section of pipework until the fluid pressure within the test system reaches a predetermined test pressure maximum; c) monitoring the fluid pressure within the test system for a predetermined period of time and recording any reductions in the fluid pressure that might be indicative of a leak in the section of pipework; d) actuating the two-way valve assembly to set up a second flow path configuration, in which the section of pipework and a second fluid holding tank are in fluid communication, and then allowing fluid to flow from the section of pipework into the second tank until the fluid pressure within the test system achieves a predetermined reduction in fluid pressure; e) measuring the volume of fluid received in the second tank and comparing the measured fluid volume with an allowable water loss calculated for the section of pipework at the predetermined fluid pressure reduction to confirm that the levels of air in the pipework are at an acceptable level; f) monitoring the pressure within the pipework for a period of 30-90 minutes to identify any reductions in pressure indicative of a leak in the section of pipework; and g) actuating a valve between the first and second tanks to facilitate the return of the test fluid from the second tank to the first tank under gravity. By employing the above method it is possible to deliver a testing procedure that conducts a pressure test capable of accounting for visco-elastic stress experienced by the pipework being tested with a single calibrated device rather than attaching and detaching a series of testing tools to carry out each of the test stages. Preferably the test fluid is returned from the second fluid storage tank to the first fluid storage tank under gravity. Returning the test fluid back to the first tank after the test is complete helps get the testing device ready for reuse in the next testing operation without the need to completely refill the device with fresh water. Preferably the method further comprises the step of monitoring the temperature of the temperature of the fluid in the test system. As noted above, monitoring the temperature of the fluid as it enters / leaves the device ensures that the testing is conducted within acceptable parameters. Preferably the method further comprises the step of filtering the fluid to remove particulates that might otherwise accumulate within the test system. Alternatively or additionally the method may further comprise sterilizing the fluid to prevent the introduction and possible build-up of bacteria within the test system. Further preferably, the fluid is sterilized by: i) introducing a biocide into the fluid; ii) subjecting the fluid to UV light and / or heat to kill bacteria in the fluid; or iii) a combination of both i) and ii). As noted above, maintaining the quality of the testing fluid not only allows the fluid to be used multiple times but it also prevents the fluid contaminating the pipework being tested. Preferably the integrity of said section of pipework may be tested both before and after the mains water supply pipework is installed in the ground and then the measurements collected in step c) are compared to identify faults that may have been formed during the installation of said section of pipework. It is envisaged that by testing the pipework both before and after it has been laid in the ground it is possible to distinguish between faults in the pipework and fault caused during the installation of the pipework. Preferably the method further comprises the step of recording data collected during the test and storing such with a unique identifier and location confirmed by GPS that is associated with the section of mains water supply pipework being tested. This enables the test results obtained by the method to be clearly indexed and retrieved as required. Additionally, the method further comprising the step collecting location data for the section of pipework being tested and storing such with the recorded data and the unique identifier. This provided even more specific characterisation of the test results for later assessment. According to a further aspect of the present invention there is provided a computer program product comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method of the present invention. Brief Description of the Drawings The present invention will now be described with reference to the preferred embodiments shown in the drawings, wherein: Figure 1 shows a preferred embodiment of the test apparatus of the present invention connected to a section of pipework from a mains water supply; Figure 2 shows a diagrammatic view of the preferred embodiment from Figure 1 in more detail; and Figure 3 is a graph showing the pressure changes throughout a pressure test conducted using the testing apparatus of the present invention. Detailed Description of the Preferred Embodiment The present invention relates to a testing apparatus for use in pressure testing mains water supply pipework, which is typically installed below the ground. The apparatus can be used to test the installation integrity of a section of mains water supply pipework system following its installation in the ground so that the installation can be signed off before moving on to the next stage of above ground construction. With that said, it is also envisaged that the testing apparatus for the present invention could also be employed to test existing mains water supply pipework system that has potentially developed a fault and has then been excavated to obtain access. Whilst it is envisaged that the testing apparatus of the present invention can be employed to test a section of pipework that comprises a single length of pipe, typically the section of pipework being tested would preferably comprise multiple pipes (e.g., water main and the service lines, home connections) and their associated connectors / junction points. This is because it is the joins between various components of the mains water supply pipework system that present the highest risk for leaks. Whilst it is envisaged that the pressure testing can be carried out on a newly installed section of pipework prior to backfilling, this would necessitate the use of abutments / anchorage to support the pipework. As such, the pressure testing method of the present invention would preferably be employed once the trench, within which the section of main water supply pipework is laid, has been partially backfilled to support the main length of pipe whilst leaving the joins / connectors exposed. Such connectors / junction points would typically require support from suitable abutments / anchorages to protect them from the potential effects of a water pressure hammer during pressure testing. It is envisaged that the apparatus of the present invention could be employed to test sections of mains water supply pipework that are as long as 500m, however it is appreciated that preferably shorter lengths would be tested. As will be appreciated from the described embodiments, in situations where the volume of test fluid required for a particular section of pipework exceeds the on-board capacity of the fluid storage tank the testing apparatus can be connected up to a supplementary water source to top up the on-board storage tank. The testing apparatus of the present invention is considered particularly suitable for conducting pressure testing on pipework made from materials that exhibit visco-electric behaviour. It will be appreciated by the skilled person that visco-elastic stress, sometimes referred to as creep, can affect the quality and accuracy of results obtained using standard pressure testing methodology. The testing apparatus of the present invention allows multi-stage testing to be carried out safely and in a reproducible manner. The present invention will now be described with reference to the preferred embodiment of the apparatus shown in the figures. In this regard, Figure 1 shows a typical test site in which a section of mains water supply pipework 1 is deployed within a trench in the ground prior to being buried by backfilling. An outlet 1a of the mains water supply pipework 1 is shown connected to the mobile water supply testing apparatus 2 of the present invention by way of a pipework engaging interface that comprises conduit 3. Although it is envisgaged that the conduit might suitably be formed from a range of flexible materials, polyeythelene (PE) is considered particularly suitable. It is envisaged that the outlet 1a should be located at the lowest point of the section of main water supply pipework being tested. The mobile water supply testing apparatus of the present invention will now be described in more detail with reference to Figure 2, which shows a diagrammatic view of the key components of the testing apparatus 2. The testing apparatus, which is again shown connected in fluid communication with the pipework outlet 1a via conduit 3, comprises a first fluid storage tank 5 and a second fluid storage tank 9. The second tank 9 is located above tank 5 to allow fluid transfer back from the second tank to the first tank via transfer pipe 16 under gravity. An actuated valve is provided on the transfer pipe 16 to manage the flow of fluid back to the first tank 5. Although not shown in Figure 2, it is envisaged that the actuated valve on the transfer pipe 16 is controlled by control means 14. It is appreciated that whilst the two fluid storage tanks are shown as being integrated within the mobile water supply testing apparatus 2, it is possible that the first water storage tank may be provided as a separate component connected via appropriate conduits to accommodate larger volumes of testing fluid. Alterntatively, when additional test fluid is required, water can be added directly to the first tank 5, via inlet connection 5a, from an alternative water supply during the testing procedure. Regardless of whether the first fluid storage tank 5 is integrated into the main body of the testing apparatus 2 or alternatively provided as a standalone tank, the first and second fluid storage tanks 5, 9 and the conduit 3 are connected to one another via a two-way valve 4 that is operable to control the direction of flow between the three key components in a variety of flow path configurations. In the first fluid flow path configuration the first fluid storage tank 5 is connected to the pipework outlet 1a via the conduit 3 to form a fluid tight flow path between the first storage tank and the pipework 1. A pump 6 is provided in line with the flow path to facilitate the delivery of pressurised test fluid from the storage tank 5 to the pipework via the two-way valve assembly 4 and the conduit 3. The first fluid flow path comprises a pressure sensing means 7 that is provided in fluid communication with the pipework 1 via the two-way valve assembly 4. Valve means 8 is provided to isolate tank 5 and pump 6 from conduit 3 once STP has been acheived when periodic testing of the pressure within the pipework can be carried out. In a second fluid flow path configuration the second fluid storage tank 9 is connected to the pipework outlet 1a via the conduit through the switched two-way valve assembly 4. The second fluid storage tank 9 comprises a volumetric gauge 10 which enables the levels of fluid in the second storage tank to be monitored by level and / or weight. The second fluid flow path comprises a pressure sensing means 11 that is provided in fluid communication with the pipework 1 via the two-way valve assembly 4. Pressure release and isolation valve 12 maintains the pressure in pipework connecting tank 9 to pipework 1 via conduit 3. It also reduces pressure under instruction, via connection route 12a, from control means 14 using data from pressure sensor 11, during the testing process (phase v of Figure 3). The testing apparatus 2 further comprises a computer operated control means 14, which is configured to oversee various aspects of the test apparatus operation and ensure that each test stage is properly managed. The control means 14 are operably connected to the two-way valve assembly 4 via connection route 4a, the pump 6, via connection route 6a and the pressure sensing means 7 and 11, via connection routes 7a and 11a. Although omitted from Figure 2 for the sake of clarity, it should be appreciated that the control means 14 is also operably connected to the actuated valve of the transfer pipe 16. Via the connection routes the computer operated control means 11 can control not only which fluid flow path configuration is in operation but it can also monitor the temperature of fluid within the pipework using temperature sensing means 13, which are connected to the control means via connection route 13a. Providing the conduit 3 with temperature sensing means 13 that monitor the temperature of fluid entering and leaving the test apparatus 2 allows the computer operated control means 14 to ensure that the temperature of fluid being used in the testing procedure is within acceptable parameters. It will be appreciated that when the temperature within the pipework exceeds 25°C the accuracy of any test results collected may be negatively affected. Although not shown in Figure 2, it is envisaged that further components may be provided to add additional benefits to the operability of the test apparatus 2. For instance, in order to prolong the working life of the test fluid and also to avoid unwanted contamination of mains water supply pipework by the test fluid, the testing apparatus of the present invention may further be provided with filtration and / or sterilisation means 15 that can ensure the quality of the testing fluid for example, the testing fluid may be sterilised by introducing a biocide into the fluid or by subjecting the fluid to UV light and / or heat to kill any bacteria in the fluid. The testing method of the present invention will now be described with reference to the figures and in particular Figure 3, which shows the pressure changes within the section of mains water supply pipework during the various test stages (indicated on Figure 3 as stages i to vi). Once the section of mains water supply pipework 1 has been selected, the test apparatus 2 is connected to the inlet / outlet of the pipework 1a via the pipework engagement interface which comprises a conduit 3 provides with connection means that are capable of forming a fluid tight seal with the pipework inlet / outlet 1a. Connecting the pipework 1 and the test apparatus 2 together in fluid communication creates the test system. Following a period of relaxation (stage i), in which the fluid pressure within the system is allowed to reach normal, atmospheric pressure, the temperature of pipework and its contents are measured to ensure the temperature is within acceptable parameters (i.e., temperatures should not exceed 25°C). Ensuring that the two-way valve assembly 4 is set to the first fluid flow path configuration, the pump 6 of the test apparatus 2 is operated to pump fluid from the first fluid storage tank 5 into the pipework 1. During the filling process a bleed valve is held open at, preferably, the highest part of the section of pipework under test to remove air. When it is considered that the air has been removed then the bleed valve will be closed and the fluid pressure within the pipework will increase to a System Test Pressure (STP). During this period of rapid increase, which is identified as stage ii in Figure 3, the pressure will preferably be increased to a STP of around 16Bar. Typically the rapid increase in pressure lasts for around 10 minutes, although this time may vary depending on operational parameters (e.g., the size of the testing apparatus and / or the pipework). The pressure level within the pipework 1 can be periodically measured by the pressure sensing means 7. The two-way valve assembly 4 remains in the first fluid flow path configuration throughout this stage of the testing. Once the pressure in the pipework 1 reaches the STP the testing apparatus 2 is operated to maintain this pressure for a period of 30 minutes (identified as stage iii in Figure 3). The pressure can be maintained by continuously or periodically operating the pump 6 with reference to the pressure readings obtained by the pressure sensing means 7. The computer operated control means 14, which are in operable contact with both the pump 6 and pressure sensing means 7, are configured to manage the operation of the pump 6 to ensure the pressure within the pipework is maintained at the STP. By automating this pressure maintenance stage in this way, the operator is free to conduct a visual inspection of the section of mains supply pipework to identify any leaks. Following the pre-determined period of sustained pressure, the control valve 8 closes and the pump 6 ceases pumping fluid into the pipework 1. The test apparatus 2 then uses the pressure sensing mean 7 to monitor the pressure within the pipework 1 for a period of 60 minutes (identified as stage iv in Figure 3). It will be appreciated that a gradual reduction of measured pressure within the test system is expected as the visco-elastic properties of the pipes in the allow them to stretch and expand under the increased pressure. The pressure readings taken by the pressure sensing means 7 over this ‘relaxation’ period are stored by the computer operated control means 11. The control means 11 monitor any changes in the pipework pressure and present the information to the operator, either via a screen on the control means or wirelessly to a phone / tablet / computer used by the operator. In the event that the loss is in pressure is above an expected level (typically about 30% of the STP), the control means will issue an appropriate alert as higher that expected pressure loss can indicate the existence of a significant leak. Although higher than expected pressure loss at this stage can be the result of increased temperatures within the pipework of the test system, this potential causation can be eliminated by continuously monitoring the temperature of fluids entering / leaving the test apparatus. The temperature levels measured by the test apparatus are fed back to the control means 14 to give context to the levels of pressure loss detected during stage iv. Assuming that the results of the initial stages are with acceptable parameters and no leaks have been detected, the test apparatus 2 moves on to the next stage of the testing procedure, which is the pressure drop test (stage v). The pressure drop test is important because air in the test section of the mains water supply pipework will lead to erroneous test data that could either give a false positive for a leak or alternatively mask smaller leaks. It is envisaged that in order for the results of the main pressure test to be as accurate as possible the levels of air within the test system needs to be a low as possible and this should have been achived during stage ii using the bleed valve. In order to conduct the pressure drop test the control means 11 operates the two-way valve to switch from the first fluid flow path configuration to the second fluid flow path configuration in which the section of pipework is provided in fluid communication with the second tank 9 via the conduit 3 of the pipework engagement interface. The fluid within the pipework is measured using pressure sensor 11 and is then rapidly reduced by the pressure release valve 12 which allows the fluid to flow from the pipework 1 into the second tank 9 until a pressure drop of between 10 and 15% of STP as set by the controller 14, has been achieved. Once the required pressure drop has been achieved, the volume of fluid ejected from the pipework into the second tank 9 is measured by use of the volumetric gauge 10 and / or by being weighed. The volume of ejected fluid is that compared to the anticipated water loss for the particular section of mains water supply pipework that is connected to the test apparatus. If the volume of fluid ejected during the pressure drop test is higher than the anticipated water loss for the section of mains water supply pipework this indicates that the levels of air within the system remain too high and further venting of the system must be carried out before the main pressure test can be carried out. The anticipated water loss, or AVmax, can be calculated using the following formula: 1 D AVmax = 1.2 x V x AP x — x---— Ew e x Er Where: V is the volume of the section of mains water supply pipework being tested in litres; △p is the measured pressure loss in kPa (e.g., between 10 and 15%STP); Ew is the bulk modulus of water in kPa; D is the internal pipe diameter in metres; e is the wall thickness of the pipe in metres; Er is the modulus of elasticity of the pipe wall in the circumferential direction in kPa. Following a successful pressure drop test (i.e., stage v), the test apparatus 2 moves on to the main test phase (indicated as stage vi in Figure 3). During the main test phase the pressure within the pipework is monitored and recorded by the test apparatus 2 for a period of at least 30 minutes. Although this monitoring period may be longer (e.g., up to 90 minutes, as represented in Figure 3 as stage vi(2)), 30 minutes is typically considered long enough to obtain a good indication of any pressure changes within the test system. As a result of the reduction in pressure within the system caused by the pressure drop test (i.e., stage v), the visco-elastic properties of the pipework lead to a contraction of the pipework (also known as rebound), which manifests itself in an increase in the measured pressure within the pipework. Against this backdrop, any falls in the measured pressure (as depicted by dashed line 17 in Figure 3) are indicative of a leak within the section of mains water supply pipework being tested provided they are no greater than 0.25 Bar. Falls in pressure that are greater than 0.25 Bar during the 30 minutes of stage vi are considered more likely to be indicative of a failure of the testing procedure rather than a leak. In circumstances where the pressure loss exceeds 0.25 Bar it is recommended that the test is reset and started again from stage i. Once the final stage of the pressure test has been concluded, and the results processed and presented by the test apparatus, the control means 14 depressurises the pipework by opening the pressure release valve 12 and also opens the actuated valve on the transfer pipe 16 to allow the fluid in tank 9 to flow into tank 5, under gravity, for use in the next pressure test. The test apparatus of the present invention allows the multiple stages of the pressure testing procedure to be carried out safely in a repeatable manner that ensures a consistent application of the testing procedure. By providing a test apparatus that can simply be connected to a section of mains water supply pipework, and then operated to carry out the various stages of testing without the need disconnect and reconnection different testing components, the risks of working with highly pressurised systems is reduced. It is envisaged that further advantages may be delivered by adopting additional preferable features in the test apparatus of the present invention. For instance, whilst the testing fluid used by the test apparatus can be used fresh for each test, it is envisaged that by providing the test apparatus of the present invention with filtration and / or sterilising means it is possible to carry out multiple tests with the same testing fluid. Treating the testing fluid both before it is delivered into the main water supply pipework and after it returns to the test apparatus 2 from the pipework 1 also helps to prevent contamination of the pipework. Examples of preferred sterilisation means include introducing a biocide into the fluid; subjecting the fluid to UV light and / or heat to kill bacteria in the fluid; or even a combination of both.

Claims

1. A mobile testing device for conducting installation integrity testing on mains water supply pipework, said device comprising:a first fluid holding tank with a pump and a second fluid holding tank with a volumetric gauge, wherein the two tanks are arranged in a configuration that allows fluid to return from the second tank to the first tank via an actuatable valve;wherein the first fluid holding tank and the second fluid holding tank are connected in fluid communication with a pipework engagement interface via conduit means that comprise pressure sensing means and a two-way valve assembly, said pipework engagement interface being configured to form a fluid-tight seal with a section of main water supply pipework; andwherein said two-way valve assembly is actuatable to switch between two alternative fluid flow path configurations, in which:a) the first tank, the pipework engagement interface and pressure sensing means are connected in a first fluid flow path configuration; andb) the second tank, the pipework engagement interface and pressure sensing means are connected in the second fluid flow path configuration.

2. The mobile testing device of claim 1, wherein the device further comprises computer operated control means that are programmed to actuate the two-way valve assembly to facilitate the flow of fluid through either of the fluid flow path configurations.

3. The mobile testing device of claim 1 or 2, wherein the computer operated control means are programmed to actuate the valve between the first and second fluid storage tanks so that fluid can return from the second tank to the first tank.

4. The mobile testing device of claim 1,2 or 3, wherein the conduit means further comprise in-line filtration and / or sterilization means.

5. The mobile testing device of claim 2, 3 or 4, wherein the computer operated control means is configured to collect data from the pressure sensing means,interpret that data for use by the system for control and the testing protocol, and store and / or export such data.

6. The mobile testing device of any of the preceding claims, further comprising temperature sensing means configured to monitor the temperature of fluid entering and leaving the device via the pipework engagement interface.

7. The mobile testing device of any one of claims 2 to 6, wherein the computer operated control means receives information from the pressure sensing means and the volumetric gauge and uses such to dictate the operation of the pump and the actuation of the two-way valve assembly.

8. The mobile testing device of any of the preceding claims, wherein the first fluid storage tank is provided with a fluid inlet that is configured to facilitate a fluid connection with a supplementary water source.

9. The mobile testing device of any one of the preceding claims, wherein the device is mounted on a wheeled base.

10. The mobile testing device of claim 9, further comprising an enclosure that houses and protects the components of the device.

11. A method of testing the installation integrity of a section of mains water supply pipework, said method comprising:a) connecting the mobile device of any one of claims 1 to 8 to said section of pipework via the pipework engagement interface to form a test system;b) actuating the two-way valve assembly to set up a first flow path configuration, in which a first fluid holding tank and the section of pipework are in fluid communication, and then pumping test fluid from the first tank into the section of pipework until the fluid pressure within the test system reaches a predetermined test pressure maximum;c) monitoring the fluid pressure within the test system for a predetermined period of time and recording any reductions in the fluid pressure that might be indicative of a leak in the section of pipework;d) actuating the two-way valve assembly to set up a second flow path configuration, in which the section of pipework and a second fluid holding tank are influid communication, and then allowing fluid to flow from the section of pipework into the second tank until the fluid pressure within the test system achieves a predetermined reduction in fluid pressure;e) measuring the volume of fluid received in the second tank and comparing the measured fluid volume with an allowable water loss calculated for the section of pipework at the predetermined fluid pressure reduction to confirm that the levels of air in the pipework are at an acceptable level;f) monitoring the pressure within the pipework for a period of 30-90 minutes to identify any reductions in pressure indicative of a leak in the section of pipework; andg) actuating a valve between the first and second tanks to facilitate the return of the test fluid from the second tank to the first tank under gravity.

12. The method of claim 11, further comprising the step of monitoring the temperature of the temperature of the fluid in the test system.

13. The method of claim 11, or 12, further comprising the step of filtering the fluid to remove particulates that might otherwise accumulate within the test system.

14. The method of claim 11, 12 or 13, further comprising sterilizing the fluid to prevent introduction and the possible build-up of bacteria within the test system.

15. The method of claim 14, wherein the fluid is sterilized by:i) introducing a biocide into the fluid;ii) subjecting the fluid to UV light and / or heat to kill bacteria in the fluid;iii) a combination of both i) and ii).

16. The method of any one of claims 11 to 15, wherein the integrity of said section of pipework is tested both before and after the mains water supply pipework is installed in the ground and then the measurements collected in step c) are compared to identify faults that may have been formed during the installation of said section of pipework.

17. The method of any one of the preceding claims, further comprising the step of recording data collected during the test and storing such with a unique identifierand location confirmed by GPS that is associated with the section of mains water supply pipework being tested.

18. The method of claim 17, further comprising the step collecting location data for the section of pipework being tested and storing such with the recorded data and 5 the unique identifier.

19. A computer program product comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method of any one of claims 11 to 18.21

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