Brochure
FIREYE PRIMELINE PRODUCTS • 51
GENERAL REFERENCE TABLES
NEMA Standard Classification Codes for Flame Safety Control Enclosures
NEMA 1— General Purpose. For indoor protection, where conditions are not unusually severe.
NEMA 2— Driptight. Designed to exclude falling moisture or dirt. Particularly applicable to cooling rooms, laundries,
etc., where condensation is prevalent. For indoor use.
NEMA 3— Weather Resistant (weatherproof). For outdoor use; designed to withstand all normal exposure to natural
elements. Controls mounted on pullout racks for easy access. With rain hood and weather seals.
NEMA 4 — Watertight. Withstands water pressure from l inch hose nozzle, 65 gallons per minute, from distance of not
less than 10 feet for five minutes. Suitable for maritime applications, breweries, etc.
NEMA 5 — Dust-tight. Equipped with dust-tight gaskets. Suitable for mills and other high-dust atmospheres.
NEMA 6 — Submersible. For submerged operation under specified pressures and time.
NEMA 7— Hazardous Locations, National Electrical Code Class l (circuit breaks in air).
NEMA 8 — Hazardous Locations, National Electrical Code Class l (circuit breaks immersed in oil).
NEMA 9 — Hazardous Locations, National Electrical Code Class 2.
NEMA 10 — Explosion-proof. Meets U.S. Bureau of Mines requirements for explosive atmospheres.
NEMA 11 — Acid or Fume Resistant. Provides for immersion of enclosed equipment in oil.
NEMA 12 — Industrial Use. Excludes oils, dust, moisture, to satisfy individual requirements.
Conversion to Symmetric Units
POWER AND HEAT BTU CONTENT OF FUELS
Grade or Type Unit BTU
1 BTU 776 ft.-lb. No.1 Oil Gallon 137,400
1 cal 0.003968 BTU Watt/hr. No. 2 Oil Gallon 139,600
1 BTU 0.293 Watt 4.2 cal/min. No. 3 Oil Gallon 141,800
1 Watt 3,413 BTU/hr No. 4 Oil Gallon 145,100
1 Watt-hr. 3.413 BTU/hr No.5 Oil Gallon 148,800
1 kW (1000
Watts)
3413 BTU/hr No. 6 Oil Gallon 152,400
1 kW/hr. 3413 BTU/hr Natural Gas cu ft. 950 to 1,150
1 hp 0.746 BTU 33,000 ft-lb./min. Propane cu ft 2,550
1 bhp 9.809 kW 33,479
BTU/hr
34.5 lb. of steam per hour.
Butane cu ft. 3,200
Quantity Standard Unit SI Unit SI Symbol
Multiplier to Convert
from Standard Unit to SI
Unit
Temperature Degrees Fahrenheit Degrees Celsius C 5/9 (F-32)
Length Inches/Feet Millimeters/meters mm/m 25.4/0.3048
Capacity—Gas Valves Cubic feet per hour Cubic meters per hour m
3
/hr 0.0283168
Control Valve
Coefficient
C
v
ak
v
bk
v
0.857
Fluid Capacity Gallons per hour Liters per second 0.001052
Heat BTU per cubic foot Megajoules per cubic meters MJm
3
0.0671
Pressure Drop Inch of water column Kilopascals kPa 0.2486
Pressure Inch of mercury Kilopascals kPa 3.3741
Pressure Pounds per square inch Kilopascals kPa 6.8948
Power (electric) Horsepower Watts/kilowatts W/kW 746/0.746
Weight Pounds Kilograms kg 0.4536