Section 50.64. Internal combustion engine generator systems

(a) Adequate combustion air. Internal combustion engine generator systems shall be provided with adequate combustion air from the exterior of the building.

(b) Gasoline engine systems. Gasoline operated engine generator systems shall be placed in a room or compartment separated from the remainder of the building by 1 hour partitions. Any doors opening into the room or compartment shall be C-label 3/4 hour fire door assemblies. Such rooms or compartments shall not be located beneath an assembly room or corridor leading therefrom unless separated by a concrete slab of at least 4 inches in thickness.

(1) Main fuel supply. If located in the building, the main fuel supply shall be buried at least 2 feet under ground, or located within a fireproof enclosure at least 12 inches in thickness; 6 inches shall be earth or sand solidly tamped, and 6 inches shall be concrete. The earth or sand shall be filled in between the tank and concrete enclosure. The fuel tanks shall be located at least 15 feet away from the heating plant, 2 feet away from foundation footings and filled from the outside of the building.

(2) Capacity of engine reservoir. No reserve supply of fuel shall be stored in the compartment or building except that a reservoir tank not exceeding 1 quart liquid capacity may be located on the engine or in the engine compartment to insure minimum delay in starting the engine. The compartment shall not be used for storage or flammable oils or other combustible material.

(c) Diesel fuel generators. Fuel supplies for diesel engines shall comply with NFPA-37, 1979 Edition.

(d) Temperature. The rooms or compartments where engines are located shall be maintained at a temperature of not less than 65°F, even if it necessitates insulated enclosures with motor operated air intake louvers and air discharge louvers, either gravity or motor operated. Heating shall be by means of indirect radiation of the room or compartment. Adequate ventilation shall be provided to prevent temperature rises in generators, engines and controls in excess of the recommendations of the manufacturer. The ambient room temperature shall not exceed 110°F even if this requires air cooling. For water cooled engines located in exterior areas, in lieu of providing an insulated enclosure, it is permissible to provide jacket water heaters to maintain the engine at a temperature of not less than 70°F nor more than 100°F, in an ambient of 10°F only when an enclosed battery box with strip heater is also provided to maintain the starting battery at a temperature of not less than 65°F. A V-type engine shall have a heater for each bank of cylinders. Only when providing such jacket water heaters and heated battery box may an enclosure be uninsulated or contain fixed immovable louvers.

(e) Foundations. Engines and generators shall be installed on solid foundations not likely to permit sagging of fuel, exhaust or lubricating oil piping and damage to parts resulting in leakage at joints. Such foundations shall be raised at least 6 inches above the floor level.

(f) Accessibility of equipment. Engine generators and controls shall be installed in a location that permits ready accessibility of parts for repair, maintenance, cleaning or replacement.

(g) Fuel strainers. A strainer shall be provided in the fuel supply line through which the fuel shall pass before reaching the valves or parts which are likely to become clogged. The strainer shall be readily accessible for cleaning.

(h) Gravity feed prohibited. Gravity feed of fuel to carburation or compression ignition engines shall be prohibited except that a reservoir tank described in subsection (b)(2) may be used.

(i) Special devices for gas systems. Systems using natural, manufactured or liquefied petroleum gas as fuel shall have suitable pressure reducing and regulating devices in the fuel line and shall have a solenoid valve that is normally closed connected in the line on the high pressure side of the engine gas regulator. The solenoid valve shall open automatically in the event of power failure and remain open until normal power is restored.

(j) Liquefied petroleum gas. Liquefied petroleum gas may be used as engine fuel under the following conditions:

(1) Cylinders shall be installed above grade with an outlet at least 5 feet away from any building opening which is below the level of such outlet.

(2) A relief valve shall be installed on the low pressure side of the primary regulator adjusted to discharge into the atmosphere at a pressure less than the maximum allowable pressure for the engine regulator. The discharge outlet shall be located not less than 5 feet horizontally from an opening into the building which is below such discharge.

(3) A solenoid operated valve shall be connected in the fuel line to the engine between the primary regulator and the engine regulator with the operating coil connected so that the valve will open automatically in the event of power failure and be closed at all other times.

(4) The fuel line shall be of sufficient size to provide adequate fuel at satisfactory pressure to run the engine generator at rated connected load.

(5) An adequate fuel supply to operate the engine generator at rated load for 1 hour shall always be maintained. A gauge to indicate fuel level shall be provided.

(6) Cylinders or tanks shall be set on a firm foundation and, in the case of school or other installations as deemed necessary by the Department, shall be enclosed by a fence with a locked gate to prevent unauthorized persons from tampering with the cylinders, tanks, regulators, and other similar equipment.

(7) Fuel and fuel cylinder or tank for emergency lighting application shall be used for no other purpose.

(k) Exhaust pipes. Exhaust pipes shall be of sufficient strength so as to withstand the service and shall be connected to the engine so that emission of sparks, flame or gas within the building is prevented. The pipes shall be adequately supported throughout their run and shall terminate outside the building at a point where the unobstructed discharge is subject to only normal atmospheric pressure and the hot gases or sparks will be discharged harmlessly and not directed against combustible material or in close proximity to fuel supply lines. Exhaust pipes shall not be connected into chimneys or flues except that a separate exhaust stack may be introduced into an existing flue if the exhaust stack extends to the top of the flue and the flue does not contain highly corrosive gases, such as products of combustion from gas, coal or oil burning appliances. An effective device shall be provided to permit prompt removal of exhaust condensation.

(l) Ignition. Electric or compression ignition shall be employed. No method of ignition shall be used that introduces open flames or exposes highly heated parts while the engine is in operation.

(m) Starting apparatus. Engine starting apparatus shall conform to one of the following arrangements:

(1) It is connected directly to the engine crankshaft and does not disengage after starting.

(2) It is connected to the engine crankshaft by gears, silent chain drives or by other approved means and does not disengage after starting or does disengage by means of an overrunning clutch.

(3) It is connected so as to engage for starting and to disengage after the engine is started if the means of engaging and disengaging the starting apparatus are by a solenoid actuated pinion used in conjunction with the over-running clutch. The starting motors, windings, drives and other devices shall be capable of continuously cranking the engine for a period of not less than 1 minute.

(n) Cranking batteries. When batteries are used to furnish energy for cranking, they shall be of sufficient capacity to start the engine within 5 seconds and to crank the engine continuously for a period of at least 5 minutes at a speed sufficient to start the engine at the end of a 5 minute cranking period.

(o) Battery charging equipment. Systems using charging batteries shall be equipped with a charging device to automatically maintain the batteries in a full charged condition. The charging device shall be capable of replacing, within a 24-hour period, the charge taken out of the batteries by a 5 minute continuous cranking period. The charger shall have an ammeter to read the rate of charge. The charger shall be permanently connected to the batteries, and no charger disconnect switch shall be permitted.

(p) Size of engine. The engine shall be of sufficient size to enable the generator set to pick up a full rated kilowatt load in one step. The generator set rating shall be determined by the criteria in this subsection. The minimum generator efficiency shall be 80%.

(q) Low oil pressure and high water temperature alarms. Engine protective and annunciator devices shall be provided as follows:

(1) Engines shall have an automatic engine speed governor.

(2) Air cooled engines shall be permitted, but not required, to have low lubricating oil pressure and high air temperature audible alarms, and automatic over-speed shutdown with audible alarm. Automatic engine shutdown for low lubricating oil pressure or high air temperature shall be permitted only when an audible preshutdown alarm is sounded.

(3) Water cooled engines shall have individual visual indicators and a common audible alarm device to announce any of the following:

(i) That the engine water jacket temperature is below 70 F.

(ii) That the engine is about to shut down due to low lubricating oil pressure or high water temperature.

(iii) That the engine has shut down due to low lubricating oil pressure, high water temperature, overspeed or failure to start after 60 or more seconds of continuous cranking.

(4) Gas or oil-fired turbine engines shall have individual indicators and a common audible alarm device to announce any of the following:

(i) That the engine is about to shut down due to low lubricating oil pressure or high engine temperature.

(ii) That the engine has shut down due to low lubricating oil pressure, high engine temperature, overspeed, flameout or failure to start after 60 or more seconds of continuous cranking.

(r) Hydrometer. A test of the specific gravity of the electrolyte shall be made at least once every 2 weeks. The manufacturer shall supply a hydrometer with each installation for this purpose.

(s) Voltmeter. A voltmeter shall be provided to indicate the voltage being generated. When polyphase systems are used, the voltmeter shall indicate all line voltage, either line to line or lines to neutral.

(t) Nameplate. In addition to the nameplate required in § 50.61(g) (relating to general requirements) with a nameplate setting forth the name of the manufacturer, model number and the engine brake horsepower for the fuel used. The generators shall be provided with a nameplate setting forth the name of the manufacturer, model number, power (W or KW) rating, current rating and voltage rating.