Method and apparatus for testing a tunnel fire suppression system

Abstract

A method for testing a tunnel fire suppression system in the form of a water deluge system having a wet side and a dry side separated by a valve, includes the step of providing a nozzle arrangement comprising a plurality of nozzles, with each nozzle disposed in or coupled to an outlet of the water deluge system. The nozzle arrangement comprises, is coupled to or operatively associated with a sensor arrangement configured to measure the pressure of air at each of the plurality of outlets of the water deluge system and output one or more output signals indicative of the pressure of the air at the one or more outlets. The method includes providing a supply of pressurised air through the water deluge system using a blower coupled to the water deluge system. The method further includes measuring the pressure of the air at the one or more outlets of the water deluge system and outputting an output signal indicative of the pressure of the air at the one or more outlets, and conveying the output signal to a processing system configured to determine from said one or more output signals the flow rate of the air supply at the one or more outlets.

Claims

1. A method for testing a tunnel fire suppression system in the form of a water deluge system having a wet side and a dry side separated by a valve, the method comprising: providing a supply of pressurized air through the water deluge system using a compressor coupled to the water deluge system; providing a sensor arrangement, wherein the sensor arrangement comprises: a sensor configured to measure a pressure of air at an inlet valve to the water deluge system and output one or more output signals indicative of a pressure of the air at the inlet valve; and a plurality of sensors configured to measure the pressure of air at each of a selected subset of outlets or all of the outlets of the water deluge system and output one or more output signals indicative of the pressure of the air at each of the subset of outlets or all of the outlets; providing a nozzle arrangement, wherein the nozzle arrangement comprises a plurality of nozzles, each nozzle disposed in or coupled to e of the subset of outlets or all of the outlets of the water deluge system, wherein the nozzle arrangement is coupled to or operatively associated with the sensor arrangement; measuring the pressure of the air at the inlet valve of the water deluge system and outputting the one or more output signals indicative of the pressure of the air at the inlet valve; measuring the pressure of the air at each of the subset of outlets or all of outlets of the water deluge system and outputting the one or more output signals indicative of the pressure of the air at each of the subset of outlets or all of the outlets; conveying the output signal signals indicative of the pressure of the air at the inlet valve and indicative of the pressure of the air at each of the subset of outlets or all of the outlets to a processing system configured to compare the one or more output signals indicative of the pressure of the air at the inlet valve with the one or more output signals indicative of the pressure of the air at each of the subset of outlets or all of the outlets and determine from the one output signals a flow rate of an air supply at each of the subset of outlets or all of the outlets.

2. The method of claim 1, comprising determining a condition of the water deluge system from the one or more output signals from each of the subset of outlets or all of the outlets.

3. The method of claim 1, further comprising the replacing a pre-existing nozzle arrangement with the nozzle arrangement.

4. The method of claim 1, comprising measuring the flow rate of the air the inlet valve of the water deluge system and outputting an output signal indicative of the flow rate of air at the inlet valve.

5. The method of claim 4, comprising comparing the output signal indicative of the flow rate of air at the inlet valve with the or more output signal(s) from each of the subset of outlets or all of the outlets.

6. The method of claim 5, comprising determining a condition of the water deluge system from the compared output signals from the inlet valve and each of the subset of outlets or all of the outlets.

7. The method of claim 6, comprising determining a condition of the water deluge system by comparing the determined flow rate of the air at each of the subset of outlets or all of the outlets to a reference signal.

8. The method of claim 1, comprising comparing the flow rate of the air supply at each of the subset of outlets or all of the outlets with a previous wet test.

9. The method of claim 1, comprising subsequently performing a wet test.

10. The method of claim 9, comprising comparing the flow rate of the air supply at ea et outlets or all of the outlets with the subsequent wet test.

11. The method of claim 1, comprising performing a sequence test to verify flow directed to each of the plurality of nozzles.

12. A method, comprising: performing the method of claim 1 at a first time period to provide a first test data set indicative of a condition of the water deluge system; performing the method of claim 1 or a wet test at a second time period to provide a second test data set indicative of the condition of the water deluge system; and outputting the first data set and the second data set.

13. An apparatus for testing a tunnel fire suppression system in the form of a water deluge system having a wet side and a dry side separated by a valve, the apparatus comprising: a compressor configured for coupling to an inlet valve of the water deluge system, the compressor configured to provide a supply of pressurized air through the water deluge system from the inlet valve to a plurality of outlets of the water deluge system; a sensor arrangement, wherein the sensor arrangement comprises a sensor configured to measure a pressure of the air at the inlet valve to the water deluge system and output one or more output signals indicative of the pressure of the air at the inlet valve; and a plurality of sensors configured to measure a pressure of the air at each of a selected subset of outlets or all of the outlets of the water deluge system and output one or more output signals indicative of the pressure of the air at each of the subset of outlets or all of the outlets; a nozzle arrangement, wherein the nozzle arrangement comprises a plurality of nozzles, each nozzle disposed in or coupled to a respective one of the subset of outlets or all of the outlets of the water deluge system, wherein the nozzle arrangement is coupled to or operatively associated with the plurality of sensors of the sensor arrangement configured to measure the pressure of air at each of the subset of outlets or all of the outlets of the water deluge system; and a communication arrangement configured to convey the one or more output signals indicative of the pressure of the air at the inlet valve and indicative of the pressure of the air at each of the subset of outlets or all of the outlets from the sensor arrangement to a processing system configured to compare the one or more outlet signals indicative of the air at the inlet valve and indicative of the pressure of the air at each of the subset of outlets or all of the outlets and determine from the output signals a flow rate of an air supply at each of the subset is or all of the outlets.

14. The apparatus of claim 13, wherein at least one nozzle of the plurality of nozzles of the nozzle arrangement comprises a metering nozzle.

15. The apparatus of claim 13, wherein at least one nozzle of the plurality of the nozzles comprises a flow tube portion.

16. The apparatus of claim 15, wherein the flow tube portion is tubular in construction.

17. The apparatus of claim 15, wherein a length of the flow tube portion is greater than a length of a nozzle portion of the at least one nozzle.

18. The apparatus of claim 15, wherein the least one nozzle is configured to receive the sensor that is associated with the respective outlet of the subset of outlets or all of the outlets.

19. The apparatus of claim 15, wherein the at least one nozzle comprises a radially extending tubular boss portion for receiving the sensor that is associated with the respective outlet of the subset of outlets or all of the outlets, the boss portion formed or coupled to the flow tube portion.

20. The apparatus of claim 13, wherein the sensor arrangement comprises a sensor configured to measure the flow rate of the air at the inlet valve, and output one or more output signals indicative of the flow rate of the air at the inlet valve.

21. A water deluge system comprising the apparatus of claim 13.

22. A tunnel comprising the water deluge system of claim 21.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other aspects will now be described, by way of example only, with reference to the accompanying drawings, in which:

(2) FIG. 1 shows a diagrammatic view of an apparatus for testing a water deluge system;

(3) FIG. 2 shows a schematic view of the apparatus shown in FIG. 1;

(4) FIGS. 3, 4, 5, 6 and 7 show sensors of the sensor arrangement of the apparatus shown in FIG. 1;

(5) FIGS. 8 to 14 show a metering nozzle of the apparatus shown in FIG. 1;

(6) FIG. 15 shows a tunnel including the apparatus of FIG. 1; and

(7) FIG. 16 shows an alternative apparatus for testing a water deluge system

DETAILED DESCRIPTION OF THE DRAWINGS

(8) Referring first to FIGS. 1 and 2 of the accompanying drawings, there is shown an apparatus 10 for testing a tunnel fire suppression system in the form of a water deluge system 12.

(9) As shown, the water deluge system 12 comprises a dry side 14 and a wet side 16 separated by deluge valve 18. The dry side 14 includes a pipe network 20 and a number of outlets 22, known collectively as a deluge set. The apparatus 10 comprises a nozzle arrangement, generally denoted 24, including a discharge nozzle 26 disposed in the outlets 22. For clarity, not all of the outlets 22 and nozzles 26 are labelled in FIG. 1. The nozzle arrangement 24 comprises, is coupled to or operatively associated with a sensor arrangement, generally denoted 28, configured to measure the pressure of air at each of the plurality of outlets 22 of the water deluge system 12 and output one or more output signals indicative of the pressure of the air at the one or more outlets 22.

(10) The illustrated apparatus 10 comprises a compressor 30, which in the illustrated apparatus 10 takes the form of a 400 SCFM (Standard Cubic Feet/Minute) air compressor. However, it will be recognised that the compressor may take any suitable form, and may for example but not exclusively comprise or take the form of a 200 SCFM (Standard Cubic Feet/Minute) air compressor to a 2000 SCFM (Standard Cubic Feet/Minute) air compressor.

(11) The compressor 30 is rated for Zone 2, as set out in the Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR). As shown in FIG. 2, the compressor 30 comprises a pump 32 and a motor 34 for driving the pump 32.

(12) In use, the compressor 30 is configured to intake air at atmospheric pressure and provide an exhaust air supply to the water deluge system 12 at higher air pressure than atmospheric pressure into and through the water deluge system 12.

(13) As shown in FIGS. 1 and 2, the apparatus 10 comprises an air conditioner 36. The air conditioner 36 is coupled to the compressor 30 by a fluid conduit 38. In the illustrated apparatus 10, the air conditioner 36 takes the form of an air dryer. The air conditioner 36 is also rated for Zone 2, as set out in the Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR).

(14) In use, the air conditioner 36 is configured to output air at a temperature of or about40 degrees C. The air conditioner 36 may be configured to control the humidity of the air supply to the deluge system 12.

(15) The apparatus 10 comprises an air receiver 40, which in the illustrated apparatus 10 takes the form of one or more storage accumulator. The air receiver 40 is coupled to the air conditioner 36 by a fluid conduit 42 (shown in FIG. 2). In the illustrated apparatus 10, the air receiver 40 comprises a 4000 Litre capacity tank. However, it will be recognised that any suitable air receiver may be utilised.

(16) As shown in FIG. 1, the apparatus 10 comprises a pressure regulation unit 44. The pressure regulation unit 44 is coupled to the air receiver 40 by a fluid conduit 46.

(17) The pressure regulation unit 44 comprises a control valve 48 (shown in FIG. 2). In the illustrated apparatus 10, the control valve 48 takes the form of a ball valve. In use, the control valve 48 regulates the flow to the desired pressure required for the test operation. The pressure regulation unit 44 is rated for Zone 1, as set out in the Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR).

(18) As shown in FIG. 2, the apparatus 10 comprises a flow meter 50. The flow meter 50 is configured to measure the flow rate of the air supplied to the water deluge system 12. In the illustrated apparatus 12, the flow meter 50 takes the form of a Coriolis flow meter. The flow meter 50 is coupled to the control valve 48 by a fluid conduit 52 and to the water deluge system 12 by a fluid conduit 54.

(19) As shown in FIG. 1, the apparatus 10 comprises a digital acquisition (DAQ) device 56 which communicates with a control console 58. The digital acquisition device 56 and/or the control console 58 are rated for Zone 1, as set out in the Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR). The control console 58 may communicate with a console 60 in a control room 62. In the illustrated apparatus 10, the control console 58 is integral to the apparatus 10. However, it will be understood that the control console 58 may alternatively be remote from the apparatus 10. As an alternative to or in addition to the console 58, the apparatus 10 may comprise a mobile device 64 which communicates with one or more of the control console 58, the control console 60, the sensor arrangement 28 or other components of the apparatus 10. In the illustrated apparatus 10, the mobile device 64 takes the form of a tablet. However, it will be recognised that the mobile device 64 may alternatively comprise any suitable mobile device such as a mobile telephone or the like. In use, the apparatus 10 may, for example, relay information relating the deluge system 12, the dry test process or recommended remedial actions to a user via the mobile device 64.

(20) In use, and as will be described further below, the compressor 30 is operable to provide a supply of air at higher pressure than atmospheric pressure into and through the water deluge system 12, the sensor arrangement 28 operable to measure the pressure of the air at the outlets 22 of the water deluge system 12 and output an output signal indicative of the pressure of the air at the associated outlet 22, which is then communicated wirelessly by a wireless communication arrangement, represented by arrows 66, to the data acquisition device 56 via a wireless receiver 68. The wireless receiver 68 is also rated for Zone 1, as set out in the Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR).

(21) In the illustrated apparatus 10, the data acquisition device 56 communicates with the control console 60 by optic line 70, although it will be recognised that any suitable means may be utilised to communicate with the control console 58, including wireless communication means.

(22) The ability of the apparatus 10 to carry out a test of the water deluge system 12 without the requirement for a wet test has a number of significant benefits. For example, the apparatus 10 obviates the time, expense, and inconvenience involved in preparing for the wet test, such as arranging receptacles to collect dispensed water from the water deluge system 12, as well as the time, expense, inconvenience and inaccuracies involved in performing the wet test. Personnel are also not exposed to water flow and are thus unimpeded in carrying out their duties. The ability of the apparatus 10 to carry out a test of the water deluge system 12 without the requirement for a wet test also reduces the risk of corrosion.

(23) As described above, the apparatus 10 comprises a sensor arrangement 28 operable to measure the pressure of the air at the outlets 22 of the water deluge system 12 and output an output signal indicative of the pressure of the air at the associated outlet 22.

(24) As shown in FIG. 1 and referring now also to FIGS. 3, 4 and 5 of the accompanying drawings, in addition to the sensor arrangement 28 being configured to measure the pressure of air at each of the plurality of outlets 22 of the water deluge system 12 comprises a sensor 72 coupled to deluge valve 18, the sensor 72 operable to measure the pressure of the air at the deluge valve 18 and output an output signal indicative of the pressure of the air at the deluge valve 18.

(25) As shown in FIG. 5, the sensor 72 comprises a pressure transducer 74, a sensor control module 76, a rechargeable battery 78 and a wireless communications transceiver 80. The pressure transducer 74 is configured to measure the pressure of the air at the deluge valve 18 of the water deluge system 12 which is communicated wirelessly to the data acquisition device 56 by the transceiver 80. The sensor control module amongst other control functions may control whether the sensor 72 should be in an awake state or a sleep state. The illustrated sensor 72 further comprises a temperature sensor 82 for measuring temperature and this data may also be transmitted and used by the apparatus 10 for beneficial analysis purposes, for example the calculation of the dew point temperature of the air at the sensor 72.

(26) As shown in FIGS. 1 and 3, the apparatus 10 is coupled to the deluge valve 18 of the water deluge system 12 and more particularly to the dry side of a drain-down valve 84 of the deluge valve 18. The sensor 72 is also coupled to or operatively associated with the dry side of the drain-down valve 84.

(27) Referring now to FIGS. 6 and 7 of the accompanying drawings, the sensor arrangement 28 comprises sensors 86 for measuring the pressure of the air at the outlets 22. As shown in FIG. 7, the sensor 86 comprises a pressure transducer 88, a sensor control module 90, a rechargeable battery 92 and a wireless communications transceiver 94.

(28) The pressure transducer 88 is configured to measure the pressure of air at the outlet 22 which is then communicated wirelessly to the data acquisition device 56 by the transceiver 94. The sensor control module 90 amongst other control functions may control whether the sensor 86 should be in an awake state or a sleep state. The illustrated sensor 86 further comprises a temperature sensor 96 for the sensor measuring temperature and this data may also be transmitted and used by the apparatus 10 for beneficial analysis purposes, for example the calculation of the dew point temperature of the air at the sensor 86.

(29) As the air exits the outlets 22, the pressure of the air is measured by the sensors 86 disposed at the outlets 22. The transceivers 94 of the sensors 86 are then operable to transmit an output signal to the data acquisition device 56 via the wireless receiver 68.

(30) The transceivers 80,94 together with the wireless receiver 68 form the communication arrangement 66 of the apparatus 10.

(31) As described above, and referring now also to FIGS. 8 to 14 of the accompanying drawings, the apparatus 10 comprises a nozzle arrangement 24 comprising a plurality of discharge nozzles 26, which in the illustrated apparatus 10 take the form of metering nozzles.

(32) As shown, each discharge nozzle 26 comprises a nozzle portion 98 which forms an outlet of the discharge nozzle 26 and a flow tube portion 100.

(33) The nozzle portion 98 forms a distal end of the discharge nozzle 26. The nozzle portion 98 is coupled to the flow tube portion 100. A proximal end portion 102 of the nozzle portion 98 is configured for coupling to a distal end portion 104 of the flow tube portion 100. In the illustrated discharge nozzle 26, the nozzle portion 98 is coupled to the flow tube portion 100 by thread connection 106.

(34) The flow tube portion 100 is tubular or substantially tubular in construction. The length of the flow tube portion 100 is greater than the length of the nozzle portion.

(35) The discharge nozzle 26 further comprises a coupler portion 108 for coupling the flow tube portion 100 to the outlet 22.

(36) The coupler portion 108 is coupled to the flow tube portion 100. In the illustrated discharge nozzle 26, the coupler portion 108 is coupled to the flow tube portion 100 by threaded nut 110 engaging thread connection 112.

(37) The discharge nozzle 26 is configured to receive the sensor 86. The discharge nozzle 26 comprises a radially extending tubular boss portion 114 for receiving the sensor 86. The boss portion 114 is formed or coupled to the flow tube portion 100.

(38) Beneficially, the elongate tubular flow tube portion 110 acts to reduce measurement errors in the measurements obtained by the sensor 86. The flow tube portion 110 directsor in other words straightensthe flow of air through the discharge nozzle 26, reducing turbulence in the flow of air which would otherwise create unstable and eddying flow patterns at the location of the pressure transducer 88.

(39) When it is desired to carry out the test, the compressor is activated to provide a supply of air at higher pressure than atmospheric pressure into and through the dry side 14 of the water deluge system 12 over a test period. As the air is at a higher pressure than the air at atmospheric pressure present within the open dry side 14 of the water deluge system 12 the air flows through the pipe network 20 to the outlets 22 where it exits the deluge system 12. The sensor 72 is configured to measure the measure the pressure of the air at the deluge valve 18 of the water deluge system 12 which is communicated wirelessly to the data acquisition device 56 by transceiver 80. The sensors 86 coupled to the outlets 22 of the water deluge system 12 measure the pressure of the air at the outlets 22 of the water deluge system 12 and output an output signal indicative of the pressure of the air at the outlets 22.

(40) The method may then comprise determining a condition of the water deluge system 12 from the acquired data. This may involve comparing the data at the deluge valve 18 with the data measured at the outlets 22. Alternatively, or additionally, the air pressure data measured at the outlets 22 may be compared with a previous test using the apparatus 10 or with previous wet test data. In this way, the condition of the water deluge system may also be monitored over time, either periodically or on a continuous basis in a manner not previously possible.

(41) As described above, the ability of the apparatus 10 to carry out a test of the water deluge system 12 without the requirement for a wet test has a number of significant benefits. For example, the apparatus obviates the time, expense, and inconvenience involved in preparing for the wet test, such as arranging receptacles to collect dispensed water from the water deluge system 12 and in bagging sensitive equipment, as well as the time, expense, inconvenience and inaccuracies involved in performing the wet test. Personnel are also not exposed to water flow and are thus unimpeded in carrying out their duties. The ability of the apparatus 10 to carry out a test of the water deluge system 12 without the requirement for a wet test also reduces the risk of corrosion in the water deluge system 12 and elsewhere in the installation.

(42) A sample calculation explaining how water flow rate can be determined by measurement of air pressure is explained for a simplified system below. For incompressible flow the pressure drop in a pipe is typically given by the Darcy Weisbach equation. The present tests are performed at very low pressure, typically with nozzle outlet pressures of less than 0.1 bar above atmospheric pressure. At these low pressures the Mach number is very low e.g. less than 0.1. At very low Mach numbers the air can be said to be in an incompressible flow regime. In reality there is compression, but the difference between using more complex compressible flow calculations and incompressible flow calculations is less than 1% error. Therefore incompressible flow calculations can used to simplify analysis.

(43) Consider a simple pipe with a nozzle at its end. The pressure loss across this pipe is calculated by:

(44) $P_{AB}=\frac{4\mathrm{ff}L}{d}\frac{1}{2}{}^2$ Where: L=Length of Pipe D=Diameter of Pipe =Velocity of fluid =Density of Fluid ff=friction factor of pipe

(45) To determine the ratio between water pressure loss and air pressure loss constants can be removed

(46) $P_{AB}=\frac{}{}\frac{}{}{}^2$ Therefore giving

(47) $\frac{P_{\mathrm{AB}\mathrm{Water}}}{P_{\mathrm{AB}\mathrm{Air}}}=\frac{{}_{\mathrm{Water}}{}_{\mathrm{Water}}^2}{{}_{\mathrm{Water}}{}_{\mathrm{Air}}^2}$ Typically seawater is used for deluge testing therefore: P.sub.Water=1027 kg/m3 P.sub.Air=1.225 kg/m3 .sub.Water=6 m/sec (typically fire systems are design to avoid flow velocities higher than 6 m/sec .sub.Air=25 m/sec (equivalent air velocity for dry-flo testing) Therefore:

(48) $\frac{P_{\mathrm{AB}\mathrm{Water}}}{P_{\mathrm{AB}\mathrm{Air}}}=50$ The following is a simplified demonstration of the comparison between air and water pressure losses.

(49) TABLE-US-00001 Pressure at A Pressure loss through Pressure at Condition (bar) pipe (bar) B (bar) Initial Wet Test/ 2 0.2 1.8 Hydraulic Simulation (Example Values) Master Dry Test 0.04 0.004 0.036 (Example Values)

(50) An initial wet test is performed to commission the system 12. During this time the density application rate is verified and spray pattern verified as fit for purpose. Typically testing is performed against the expected outputs from a hydraulic modelling package.

(51) Once the system 12 has been verified and the pressure losses in water determined for the pipe network, a dry test using the apparatus 10 is performed which then determines the losses in air, this is known as the Master signature.

(52) After a period of time, for example 1 year, a further dry test using the apparatus is performed, however now there is debris built up within the line (e.g. a spurious release swept marine debris into the pipework).

(53) With the same inlet pressure at A the pressure losses are higher due to the restriction within the line leading to a lower outlet pressure.

(54) TABLE-US-00002 Pressure at A Pressure loss through Pressure at Condition (bar) pipe (bar) B (bar) Second Dry-flow 0.04 0.028 0.012 Test (Example values)

(55) The pressure at B for the same inlet pressure at A would now be:
P.sub.AB Water=50P.sub.AB Air
P.sub.AB Water=500.012=0.6 bar

(56) If the nozzle at B had a typical K factor of 25 the flow rate at B during initial test was:

(57) $Q\left(\frac{\mathrm{liters}}{\min }\right)=23P_{B\mathrm{Water}}$$Q\left(\frac{\mathrm{liters}}{\min }\right)=23\sqrt{1.8}=30L/\min$ But is now

(58) $Q\left(\frac{\mathrm{liters}}{\min }\right)=23\sqrt{0.6}=17L/\min$

(59) Accordingly, the above allows the condition of the deluge system to verified.

(60) An example of a test regime employing the apparatus is described below.

(61) On first application, a wet test and/or an inspection is carried out to the deluge system 12 to determine whether the deluge system 12 is in good condition, to determine whether the nozzles are seeing the correct pressures, to determine how long it takes for the most remote nozzle to reach the desired pressure, to determine whether the spray pattern is correct, and to determine whether the flow in L/m.sup.2/min. The drains (not shown) may also be checked to ensure they are functioning correctly.

(62) The pressure at the inlet and outlet nozzles to which the sensor arrangement 26 of the apparatus 10 is measured.

(63) The apparatus 10 is operated to remove the water by flowing at maximum rate, for example for 5 minutes to 20 minutes depending on the size of the deluge system 12.

(64) The compressor 30 slowly sweeps up through flow until it reaches maximum pressure. The sensor arrangement 28 monitors the pressure and the communication arrangement relays the detected pressure data to the processing system, control station and/or data store. This forms a master signature for the system 12.

(65) The apparatus 10 is operable to check for problems in the pipework or nozzles by breaking the system 12 down into sections. By breaking the system 12 into distinct sections, the apparatus creates a priority list for operators if problems are found depending on the severity of a given restriction.

(66) It will be recognised that the inlet pressure recorded during the master signature ramp is a unique property of a clean system. Thus, if a new signature pressure response is matched to the master signature then there are no restrictions.

(67) The pressure output of the compressor 30 is then reduced so that the compressor 30 enters the incompressible flow regime. The apparatus 10 is then operated and the flow for the particular test determined as described above.

(68) The airflow requirement for testing will change for different systems, however for an example 12 nozzle system it is estimated that approximately 200 ft.sup.3/min compressed air will be required at 0.25 Bar at the nozzles.

(69) The pressure loss through the nozzles will be approximately .Math..Math.U.sup.2 regardless of the fluid (assuming incompressible fluids).

(70) Hence, for the same pressure drop in both fluids, (.Math..Math.U.sup.2).sub.w=(.Math..Math.U.sup.2).sub.a where w=water and a=air.
Hence U.sub.a/U.sub.w(1000/1.2).sup.1/229 [U=velocity]
Hence V.sub.a/V.sub.w(1000/1.2).sup.1/229 [V=volumetric flow rate]

(71) The nozzles are designed for a supply of 285 l/min of water with a pressure drop of 0.5 bar. This implies 202 l/min for water with a pressure drop of 0.25 bar, and therefore about 5860 l/min air for a pressure drop of 0.25 bar
5860 in5.86 m.sup.3/min200 ft.sup.3/min @0.25 bar

(72) Whilst this estimate will allow for planning, each system will be fully simulated on software to understand what the expected air pressure at each nozzle will be for a fully compliant system.

(73) FIG. 15 shows a tunnel T comprising the apparatus 10.

(74) It will be recognised that the apparatus described above is merely exemplary and that various modifications may be made without departing from the scope of the claimed invention.

(75) For example, FIG. 16 shows an alternative apparatus 1010. The apparatus 1010 is similar to the apparatus 10, with the difference that the compressor 30 and air receiver 40 have been replaced with a blower 1030.

(76) The blower 1030 is disposed on a movable skid 1116 having wheels 1118 and is coupled to deluge valve 18 via a fluid conduit 1120. In the illustrated apparatus 1010, the blower 1030 comprises a pump 1032 in the form of multi-stage centrifugal pump and a motor 1034.

(77) In use, the blower 1030 is configured to intake air at atmospheric pressure and provide an exhaust air supply to the water deluge system 12 at higher air pressure than atmospheric pressure.

(78) Beneficially, the blower 1030 is capable of directing a flow of air at high flow and relatively low gauge pressure, i.e., higher pressure than atmospheric pressure but lower than high pressure air systems, into and through the water deluge system 12, and thus obviates or at least reduces the requirement for a gas source such as an accumulator, an air receiver such as a bank of compressed air cylinders and/or a pressure regulator skid.

(79) The blower 1030 occupies a relatively small footprint in comparison to conventional test apparatus. This is particularly beneficial in offshore installations, such as platform, rigs and the like, due to the size and weight limitations for transportation to/from the installation and/or where deck space is typically limited and which may prevent conventional test equipment from being installed on a permanent basis.

(80) As described above, the apparatus described above is merely exemplary and that various modifications may be made without departing from the scope of the claimed invention. For example, the apparatus may alternatively comprise an air mover.