FIRE SAFETY INVESTIGATION REPORT

Transcription

New Zealand Fire Service
Fire Engineering Unit
A simple comparison of a new internally
ferruled instantaneous coupling with that
currently used on NZFS hose
This simple test compares the flow rates and pressure losses
of existing NZFS fire hose couplings and the new internally
ferruled coupling from PSL.
Document Information
Date:
Revision:
Author:
20 September 2011
2
Jeff Parkinson
1. Table of contents
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Table of contents ................................................................................................... 2
Executive Summary ............................................................................................... 3
Introduction............................................................................................................ 3
Method .................................................................................................................. 4
Coupling dimensions ............................................................................................. 5
Layout and equipment used................................................................................... 6
Results .................................................................................................................. 8
Other observations ................................................................................................ 9
Conclusions ........................................................................................................... 9
Recommendations ............................................................................................... 10
P:\EIRSA\ENGINEERING\S25 SPECIAL PROJECTS\S25.04 AUCKLAND PROJECTS\FIRE FIGHTING WATER\HOSE COUPLING TEST\A COMPARISON OF
INSTANTANEOUS FIRE SERVICE HOSE COUPLINGS - NZFS REPORT V2.DOCX
Page 2 of 10
2. Executive Summary
Phillips & Smith Limited (PSL) have introduced a new internally ferruled (I/F)
instantaneous coupling for fire hose that meets the requirements of the following
standards:
o
BS 336:2010 – Specification for fire hose couplings and ancillary equipment
o
BS 6391:2009 – Specification for non-percolating layflat delivery hose and hose
assemblies for fire fighting purposes (with the exception of Part 10.2)
o
SNZ PAS 4505:2007 – Specification for Firefighting Waterway Equipment
A series of simple comparative pressure and flow tests were carried out to investigate if
this new design offers any improvements when compared to the existing wire fixed
coupling currently in use. The test were undertaken at the NZFS Mount Wellington
Training Centre on 1st August 2011.
The results showed that hose fitted with the new I/F coupling had an increase in water
flow in the range of 2.4% - 24.4% over the tests undertaken with 45 mm and 70 mm
diameter fire hose.
3. Introduction
The NZFS are considering changing the type of couplings on their lay flat hose from
those that are secured externally by 20 turns of galvanized mild steel wire to a new
internally copper ferruled (I/F) design manufactured by PSL.
The Fire Engineering Unit was commissioned by Ross Taylor (Auckland Region Logistics
Manager) to record preliminary measurements and compare the pressure loss and flow
rates of water over prescribed lengths of 45 mm and 70 mm diameter hose with both
coupling types.
Page 3 of 10
4. Method
A NZFS Type 2 appliance with a Darley fire pump was connected to a single 90 mm
feeder length and a standpipe shipped to a hydrant to provide the water supply. Three
lengths of hose were connected and measurements of the running pressure at the pump
and at the end of the three 25 m lengths were recorded using recently calibrated gauges.
The final flow rate was recorded using a Giddens flow gauge that had been calibrated on
the day of the test.
The following combinations of hose were used for this test:
3 x 25 m lengths of 45 mm diameter fire hose
3 x 25 m lengths of 70 mm diameter fire hose
3 x 25m lengths of 70 mm and 1 x ‘branch mans’ length: (1 x 25 m length of 45mm
diameter hose)
For accuracy, the pump pressure was set at 1050 kPa using the gauge connected to the
delivery outlet rather than by using the gauge on the pump appliance.
Page 4 of 10
5. Coupling dimensions
The new I/F couplings have a larger internal diameter as shown in the table and figures
below.
Item
Internal diameter (mm)
Female 45 mm - wire fixed
Female 45 mm I/F
Female 70 mm – wire fixed
Female 70 mm I/F
Male – all sizes both types
33
45
56
63
56
45 mm - wire fixed
45 mm – I/F
Figure 1 – 45 mm hose
70 mm – I/F
70 mm - wire fixed
Figure 2 – 70 mm hose
Page 5 of 10
6. Layout and equipment used
As the ground had a slight gradient the hose was run out from the pump with an equal
length up and down slope. The flow gauge and pump outlet were placed at
approximately the same level and all hose was laid over the same route. This layout
ensured consistency in the tests.
Pressure gauges
Flow meter
Figure 3 - Layout of pump, hose and flow gauge
Page 6 of 10
Figure 4 - Pressure gauge at Pump
Figure 5 - Pressure gauge at end of hose lengths before flow gauge
Figure 6 - Giddens flow gauge
Page 7 of 10
7. Results
Hose
Pump Pressure
(kPa)
Flow Meter Ring
Size
Hose Pressure
(kPa)
Flow
(l/min)
3x 45 mm wire fixed
1050
D3
40
700
3x 45 mm I/F
1050
D3
100
880
3x 70 mm wire fixed
1050
D5
340
2120
3x 70 mm I/F
1050
D5
340
2170
3x 70mm & 1x 45mm
wire fixed
1050
D3
80
980
3x 70mm & 1x 45mm I/F
1050
D3
190
1220
Diff.
(l/min)
180
50
240
P:\EIRSA\ENGINEERING\S25 SPECIAL PROJECTS\S25.04 AUCKLAND PROJECTS\FIRE FIGHTING WATER\HOSE COUPLING TEST\A COMPARISON OF INSTANTANEOUS FIRE SERVICE HOSE COUPLINGS - NZFS REPORT V2.DOCX
Page 8 of 10
8. Other observations
The figure below show the overall shape of the hose when traditionally made up on the
female coupling:
Figure 7 - Hose made up on female coupling.
As can be seen, the left hand hose (I/F coupling) is more circular in shape that of wire
fixed on the right which is more oval in shape. When the I/F coupling hose was run out it
paid out more evenly compared to the wire fixed hosed. This would be due to the
location of the lugs (axis of rotation) being more central on the I/F hose compared to the
wire fixed hose which is more offset due to the overall length of the female coupling - a
line drawn through the lugs on the images above illustrates this. Similar observations
were also made when the hose was made up on the female coupling.
9. Conclusions
The intent of this test was to simply measure, record and compare the pressure loss and
flow rates for a limited sample of hoses when flowing water at a standard pump operating
pressure of 1050kPa.
As expected, the larger internal diameter of the I/F couplings resulted in a lower pressure
loss and a greater flow of water compared to hose with wire fixed couplings. However, as
the internal diameter of the male coupling was 56 mm for all hose this became a constant
reduction for all 70 mm hose, but not 45 mm diameter hose.
The recorded additional flows were in the range of 50 - 240 l/min (2.4% -24.4%) when
using the new I/F couplings on typical operational lengths of hose. This will result in more
water being available for fire fighting purposes.
Page 9 of 10
10. Recommendations
Based on the results obtained from this simple comparative test it is recommended that
field trials be undertaken by operational crews across the country using the I/F couplings
on the 45mm ‘branchmans’ length to gauge feedback on what practical advantages are
obtained.
Further full range tests should also be carried out using in-line magnetic flow meters to
accurately establish the pressure curves for hose with this I/F coupling over a range of
operating pressures, flow rates and hose lengths to develop new pressure loss tables.
The actual increase in fire fighting efficiency in terms of reduced fire extinguishing times
should also be the subject of further study if this new I/F coupling is procured.
Page 10 of 10

FIRE SAFETY INVESTIGATION REPORT

Transcription

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