20
Noise
It is recommended that all generating sets installed at
roof level have sound proof enclosures fitted or are
installed in room with full inlet and outlet sound
attenuators and critical grade residential silencers. A
sound level of 75 dB (A) at 1 m. is a substential reduction
and equal to a normal office environment.
Fuel Supply
A very limited amount of fuel storage is permitted at roof
level. Weight and fire considerations are paramount. In
general, a ‘day tank’ for each set is permitted but even
this may be limited to 450 liters by some local planning
and Fire Authorities. It is essential to obtain the approval
from Authorities for the fuel system.
The bulk storage will be at ground level and subject to
the Fire Regulations governing all safety aspects. Fuel
will be pumped up to the day service tank which will
normally have high and low float level regulator fitted to
control the pump motor.
Exhaust and Air flows
Few problems are likely to be encountered with either
exhaust or air flows at roof top levels and this is a major
advantage with this type of location. If the roof level is
below adjoining buildings, the direction of the exhaust
system should be carefully sited and prevailing winds
taken in to consideration. A vertical stack with a weather
cap is occasionally recommended if offices with open
windows are in close proximity.
Air flow inlet areas should be kept clear of any obstructions
likely to restrict the air intake passage. Air outlet is unlikely
to cause any problems but again prevailing winds should
be considered as gale force winds blowing straight into
the air outlet may cause restriction. As a solution use
angled outlet louvers to overcome this problem
Cabling
Cabling is the most expensive item as a result of roof
top installation. It is recommended that the control cubicle
containing the change over contractors be located as
close to the buildings incoming public power supply as
possible. This will limit main power cable run to minimum.
Control cables will still have to be run up to the roof level
but these considerations are small core cables. It is
recommended that the generator’s control system,
sensing and instrumentation, be retained in close
proximity to the installed generator.
IMPORTANT CONVERSIONS
Pressure
1 kg/cm
2
= 14.2 PSI
= 32.81 ft. of water
= 10 m of water
1 Atm = 1.033 kg/cm
2
= 14.7 PSI
1 PSI = 0.7 m of water
= 2.3 ft of water
= 6.89 kPa
1” of Hg = 13.6” of water
Length
1 m = 3.28 ft.
= 39.37 inch
= 100 cm.
1 Inch = 25.4 mm
Mass
1 kg = 2.2 lb.
Power
1 kW = 1.34 HP
= 56.92 BTU/min
1 HP = 0.746 kW
1 KCAL/min = 14.34 kW
Area
1 m
2
= 10.76 ft
2
= 1550 sq. inch.
= 10000 cm
2
1 sq. Inch = 645.2 mm
2
Velocity
1 m/sec = 3.28 ft/sec.
= 196.85 ft/min.
Flow
1 lt/sec = 2.12 CFM
1 lt/min = 0.2642 GPM
1 m
3
/min = 35.3 CFM
= 16.7 ltrs./sec.
Volume
1 m
3
= 35.31 ft 3
= 1000 ltrs.
1 ft
3
= 28.32 ltrs.
1 gallon = 3.78 ltrs.
Engine HP =
KVA x P.F.
+ Fan HP + bat. alt. HP
0.746 x Alt. efficiency
KW (Three Phase) =
1.732 x V x I
x P.F.
1000
KW (Single Phase) =
V x I
x P.F.
1000
To Next Page
Loading...