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(continued)
(3) Length of trap arm. Fixture traps shall be located within the distance given in 280.611(c)(5). Not more than one trap shall connect to a trap arm.
(g) Offsets and branch fittings.
(1) Changes in direction. Changes in direction of drainage piping shall be made by the appropriate use of aproved or listed fittings, and shall be of the following angles: 11-1/4, 22-1/2, 45, 60, or 90 degrees; or other approved or listed fittings or combination of fittings with equivalent radius or sweep.
(2) Horizontal to vertical. Horizontal drainage lines, connecting with a vertical pipe shall enter through 45-degree 'Y' branches, 60-degree 'Y' branches, long-turn 'TY' branches, sanitary 'T' branches, or other approved or listed fittings or combination of fittings having equivalent sweep. Fittings having more than one branch at the same level shall not be used, unless the fitting is constructed so that the discharge from any one branch cannot readily enter any other branch. However, a double sanitary 'T' may be used when the drain line is increased not less than two pipe sizes.
(3) Horizontal to horizontal and vertical to horizontal. Horizontal drainage lines connecting with other horizontal drainage lines or vertical drainage lines connected with horizontal drainage lines shall enter through 45-degree 'Y' branches, long-turn 'TY' branches, or other aproved or listed fittings or combination of fittings having equivalent sweep.
(h) Grade of Horizontal Drainage Piping. Except for fixture connections on the inlet side of the trap, horizontal drainage piping shall be run in practical alignment and have a uniform grade of not less than 1/4 inch per foot toward the mobile home drain outlet. Where it is impractical, due to the structural features or arranagement of any mobile home, to obtain a grade of 1/4 inch per foot, the pipe or piping may have a grade of not less than 1/8 inch per foot, when a full size cleanout is installed at the upper end.
280.611. Vents and Venting.
(a) General Each plumbing fixture trap shall be protected against siphonage and back pressure, and air circulation shall be ensured throughout all parts of the drainage system by means of vents installed in accordance with the requirements of this section and as otherwise required by this standard.
(b) Materials.
(1) Pipe. Vent piping shall be standard weight steel, wrought iron, brass, copper tube DWV, listed plastic, cast iron or other approved or listed materials.
(2) Fittings. Appropriate fittings shall be used for all changes in direction or size and where pipes are joined. The material and design of vent fittings shall conform to the type of piping used. (i) Fittings for screw pipe shall be cast iron, malleable iron, plastic, or brass, with standard pipe threads. (ii) Fittings for copper tubing shall be cast brass or wrought copper. (iii) Fittings for plastic piping shall be made to approved applicable standards. (iv) Brass adaptor fittings or wrought copper shall be used to join copper tubing to threaded pipe. (v) Listed rectangular tubing may be used for vent piping only providing it has an open cross section at least equal to the circular vent pipe required. Listed transition fittings shall be used.
(c) Size of vent piping.
(1) Main vent. The drain piping for each toilet shall be vented by 1-1/2 inch minimum diameter vent or rectangular vent of venting cross section equivalent to or greater than the venting cross section of a 1=1/2 inch diameter vent, connected to the main drain by one of the following methods:
(i) A 1-1/2 inch diamter (min.) individual vent pipe or equivalent directly connected to the toilet drain within the distance allowed in 280.611(c)(5), for 3-inch trap arms undiminished in size through the roof,
(ii) A 1-1/2 inch diameter (min.) continuous vent, or equivalent, indirectly connected to the toilet drain piping through a 2-inch wet-vented drain that carries the waste of not more than one fixture, or,
(iii) Two or more vented drains when at least one is wet-vented, or 2-inch diamter (minimum), and each drain is separately connected to the main drain. At least one of the drains shall connect downstream from the toilet within the distance allowed in 280.611(c)(5) for 3-inch trap arms.
(2) Individual vents. Each individually vented fixture with a 1-1/2 inch or smaller trap shall be provided with a vent pipe equivalent in area to a 1-1/4 inch nominal pipe size. The main vent, toilet vent and relief vent, and the continuous vent of wet-vented systems shall have an area equivalent to 1-1/2 inch nominal pipe size.
(3) Common Vent. When two fixture traps located within the distance allowed from their vent have their trap arms connected separately at the same level into an approved double fitting, an individual vent pipe may serve as a common vent without any increase in size.
(4) Intersecting Vents. Where two or more vent pipe joined together, no increase in size shall be required; however, the largest vent pipe shall extend full size through the roof.
(5) Distance of fixture trap from vent shall not exceed the values given in the following Table:
MAXIMUM DISTANCE OF FIXTURES FROM VENT TRAP
Size of fixture drain Distance trap
(inches) to vent
1-1/4 4 ft. 6 in.
1-1/2 4 ft 6 in.
2 5 ft.
3 6 ft.
(d) Anti-siphon trap vent. An anti-siphon trap vent may be used as a secondary vent system for plumbing fixtures protected by traps not larger than 1-1/2 inches, when installed in accordance with the manufacturer's recommendations and the following conditions: (i) Not more than two fixtures individually protected by the device shall be drained by a common 1-1/2 inch drain. (ii) Minimum drain size for there or more fixtures individually protected by the device shall be 2 inches. (iii) A primary vent stack must be installed to vent the main drain at the point of heaviest drainage fixture unit loading. (iv) The device shall be installed in a location that permits a free flow of air and shall be at least 6 inches above the top of the trap arm. (v) materials for the anti-siphon trap vent shall be as follows: cap and housing shall be listed acrylonitrile- butadiene styrene, DWV grade; stem shall be DWV grade nylon or acetal; spring shall be stainless steel wire, type 302; sealing disc shall be neoprene, conforming to ASTM C564-70, or, silicone rubber, low and high temperature and tear resistant, conforming to F.S. ZZ-R-765B and MIL-L-10547.
(e) Grade and connections.
(1) Horizontal vents. Each vent shall extend vertically from its fixture 'T' or point of connection with the waste piping to a point not less than 6 inches above the extreme flood level of the fixture it is venting before offsetting horizontally or being connected with any other vent pipe. Vents for horizontal drains shall connect above the centerline of the drain piping ahead (downstream) of the trap. Where required by structural conditions, vent piping may offset below the rim of the fixture at the maximum angle or height possible.
(f) Vent terminal.
(1) Roof extension. Each vent pipe shall extend through its flashing and terminate vertically, undiminished in size, not less than 2 inches above the roof. Vent openings shall not be less than 3 feet away from any motor-driven air intake that opens into habitable areas.
(2) Flashing. The opening around each vent pipe shall be made watertight by an adequate flashing or flashing material.
(g) Vent caps. Vent caps, if provided, shall be of the removable type (without removing the flashing from the roof). When vent caps are used for roof space ventilation and the caps are identical to vent caps used for the plumbing system, plumbing system caps shall be identified with permanent markings.
280.612. Test and Inspection.
(a) Water system. All water piping in the water distribution system shall be subjected to a pressure test. The test shall be made by subjecting the system to air or water at 100 psi for 15 minutes without loss of pressure.
(b) Drainage and vent system and plumbing fixtures. The waste and vent system shall be tested by one of the three following alternate methods for evidence or indication of leakage:
(1) Water test. Before plumbing fixtures are connected, all of the openings into the piping shall be plugged and the entire piping system subjected to a static water test for 15 minutes by filling it with water to the top of the highest vent opening. There shall be no evidence of leakage.
(2) Air test. After all fixtures have been installed, the traps filled with water, and the remaining openings securely plugged, the entire system shall be subjected to a 2-inch (manometer) water column air pressure test. If the system loses pressure, leaks may be located with smoke pumped into the system, or with soap suds spread on the exterior of the piping (Bubble test).
(3) Flood level test. The mobile home shall be in a level position, all fixtures shall be connected, and the entire system shall be filled with water to the rim of the toilet bowl (tub and shower drains shall be plugged). After all trapped air has been released, the test shall be sustained for not less than 15 minutes without evidence of leaks. Then the system shall be unplugged and emptied. The waste piping above the level of the toilet bowl shall then be tested and show no indication of leakage when the high fixtures are filled with water and emptied simultaneously to obtain the maximum possible flow in the drain piping.
(c) Fixture test. The plumbing fixtures and connections shall be subjected to a flow test by filling them with water and checking for leaks and retarded flow while they are being emptied.
(d) Shower compartments. Shower compartments and receptors shall be tested for leaks prior to being covered by finish material. Each pan shall be filled with water to the top of the dam for not less than 15 minutes.
Subpart H. Heating, Cooling and Fuel Burning Systems
280.701. Scope.
Subpart H of this standard covers the heating, cooling and fuel burning equipment installed within, on or external to a mobile home.
280.702. Definitions.
(a) The definitions in this subpart apply to Subpart H only.
(1)"Accessible," when applied to a fixture, connection, appliance or equipment, means having access thereto, but which may require may require the removal of an access panel, door or similar obstruction.
(2)"Air Conditioner Blower Coil System" means a comfort cooling appliance where the condenser section is placed external to the mobile home and evaporator section with circulating blower attached to the mobile home air supply duct system. Provision must be made for a return air system to the evaporator/blower section. Refrigerant connection between the two parts of the system is accomplished by tubing.
(3)"Air Condintioner Split System" means a comfort cooling appliance where the condenser section is placed external to the mobile home and the evaporator section incorporated into the heating appliance or with a separate blower/coil section within the mobile home. Refrigerant connection between the two parts of the system is accomplished by tubing.
(4)"Air Conditioning Section" means that portion of a refrugerated air cooling or (in the case of a heat pump) heating system which includes the refrigerant pump (compressor) and the external heat exchanger.
(5)"Air Condintioning Evaporator Section" menas a heat exchanger used to cool or (in the case of heat pump) heat air for use in comfort cooling (or heating) the living space.
(6)"Air Conditioning Self Contained System" means a comfort cooling appliance combining the condenser section, evaporator and air circulating blower into one unit with connecting ducts for the supply and return air systems.
"Air Duct" means conduits or passage ways for conveying air to or from heating, cooling, air conditioning or ventilation equipment, but not including the plenum.
"Automatic Pump (Oil Lifter)" means a pump, not an integral part of the oil-burner appliance, that automatically pumps oil from the supply tank and delivers the oil under a constant head to an oil-burning appliance.
(9)"Btu. British Thermal Units" means the quantity of heat required to raise the temperature of one pound of water one degree Fahrenheit.
(10)"Btuh" means British thermal units per hour.
(11)"Burner" means a device for the final conveyance of fuel or a mixture of fuel and air to the combustion zone.
(12)"Central Air Conditioning System" means either an air conditioning split system or an external combination heating/cooling system.
(13)"Class O Air Ducts" means ducts of materials and connectors having a fire-hazard classification of zero.
(14)"Class 1 Air Ducts" means ducts of materials and connectors having a flame-spread rating of not over 25 without evidence of continued progressive combustion and smoke-developed rating or not over 50.
(15)"Class 2 Air Ducts" means ducts of materials and connectors having a flame-spread rating of not over 50 without evidence of continued progressive combustion and a smoke-developed rating of not over 50 for the inside surface and not over 100 for the outside surface.
(16)"Clearance" means the distance between the appliance, chimney, vent, chimney or vent connector or plenum and the nearest surface.
(17)"Connector-Gas Appliance" means a flexible or semi-rigid connector listed as conforming to ANSIS Standard Z21.24, Metal Connectors for Gas Appliance, used to convey fuel gas, three feet or less in length (six feet or less for gas ranges(, between a gas outlet and a gas appliance in the same room with the outlet.
(18)"Energy Efficiency Ratio (EER)" means the ratio of the cooling capacity output of an air conditioner for each unit of powe input.
Capacity (Btuh)
EER = -------------------
Power input (watts)
(19)"External Combustion Heating System" means a comfort conditioning system placed external to the mobile home with connecting ducts to the mobilt home for the supply and return air systems.
(20)"Factory-Built Fireplace" means a hearth, fire chamber and chimney assembly composed of listed factory-built components assembled in accordance with the terms of listing to form a complete fireplace.
(21)"Fireplace Stove" means a chimney connected solid fuel-burniburning stove having part of its fire chamber open to the room.
(22)"Fuel Gas Piping System" means the arrangement of piping, tubing, fittings, connectors, valves and devices designed and intended to supply or control the flow of fuel gas to the appliance(s).
(23)"Fuel Oil Piping System" means the arrangement of piping, tubing, fittings, connectors, valves and devices designed and intended to supply or control the flow of fuel oil to the appliance(s).
(24)"Gas Clothes Dryer" means a device used to dry wet laundry by means of heat derived from the combustion of fuel gases.
(25)"Gas Refrigerator" means a gasburning appliance which is designed to extract heat from a suitable chamber.
(26)"Gas Supply Connection" means the termical end or connection to which a gas supply connector is attached.
(27)"Gas Supply Connector Mobile Home" means a listed flexible connector designed for connecting the mobile home to the gas supply source.
(28)"Gas Vents" means factory-built vent piping and vent fittings listed by an approved testing agency, that are assembled and used in accordance with the terms of their listings, for conveying fuel gases to the outside atmosphere. (i) "Type B Gas Vent" means a gas vent for venting gas appliance with draft hoods and other gas appliances listed for use with Type B Gas Vents. (ii) "Type BW Gas Vent" means a gas vent for venting listed gas-fired vented wall furances.
(29)"Heat Producing Appliance" means all heating and cooking appliances and furl burning appliances.
(30)"Heating Appliance" means an appliance for comfort heating or for domestic wate heating.
(31)"Liquefied Petroleum Gases." The terms "Liquefied petroleum gases." "LPG" and "LP-Gas" as used in this standard shall mean and include any material which is composed predominantly of any of the following hydrocarbons, or mixtures of them: propane, prophylene, butanes (normal butane or isobutane), and butylenes.
(32)"Plenum" means as air compartment which is part of an air-distributing system, to which one or more ducts or outlets are connected. (i) Furance supply plenum is a plenum attached directly to, or an intergral part of, the air supply outlet of the furance. (ii) Furance return plenum is a plenum attached directly to, or an integral part of, the return inlet of the furniture.
(33)"Quick-Disconnect Device" means a hand-operated device which provides a means for connecting and disconnecting a gas supply or connecting gas systems and which is equiped with an automatic means to shut off the gas supply when the device is disconnected.
(34)"Readily Accessible" means direct access without the necessity of removing any panel, door, or similar obstruction.
(35)"Roof Jack" means that portion of a mobile home heater flue or vent assembly, including the cap, insulating means, flashing, and ceiling plate, located in and above the roof of a mobile home.
(36)"Sealed Combustion System Appliance" means as appliance which by its inherent design is constructed so that all air supplied for fombustion, the conbustion system of the appliance, and all products of combustion are completely isolated from the atmosphere of space in which it is installed.
(37)"Water Heater" means an appliance for heating water fordomestic purposes other than for space heating.
Type ANSI UL Other
Standards
---------------------------------------------------------------------
Appliances::
Air conditioners, central 465
cooling
Liquid fuel-burning heating
appliances
for mobile homes & travel A 147-1-1969 307-
trailers (-
A-
)-
--
1-
9-
69
Electric Air Heater 1025
Electric Baseboard Heating 1042
Equipment
Electric Central Air-Heating 1096
Equpiment
Gas-heating appliance for 307-
mobile homes & travel (-
b-
)-
--
1-
9-
65
trailers
Gas clothes dryers Z21.5.1-1972
Z21.5.1a-1973
Z21.5.1b.1974
Commercial gas-fired &
electrically-heated hot
water generating equipment NSF 5-1959
Gas-fired absoption summer air Z21.40.1-1973
conditioning appliances
Z21.40.1b-1974
Gas-fired gravity & forced air Z21.47-1973
central
furances Z21.47a-1974
Gas-fired gravity & fan-type Z21.44-1973
sealed
combustion system wall Z21.44a-1974
furances
Z21.44b-1975
Commercial cooling & warming NSF 4-1967
equipment
Household cooking gas Z21.1-1972
appliances
Z21.1a.1974
Refigerators using gas fuel Z21.19-1971
Z21.19a-1972
Z21.19b-1973
Automatic storage type water Z21.10.1-1974
heaters with
input less than 75,000 Btu/h Z21.10.1a-1975
Heating equpiement, electric 1096
central air
Heat pumps 559
Ferrous pipe and fittings:
Black & hot dipped zinc-coated
(galvanized)
welded ASTM
A120-1972a:
and seamless steel pipe for WW-P-406D-19-
ordinary uses 73
Electric-resistance welded ASTM
coiled steel tubing for gas & A539-1973
fuel oil lines.
Pipe threads B2.1-1968
Wrought steel & wrought iron B36.10-1970
pipe
Nonferrous pipe, tubing, and
fittings:
Seamless copper wate tube ASTM B88-1972
Seamless copper tube for air
conditioning &
refrigeration field service ASTM
B280-1973
Metal connectors for gas
appliances#Z21.24-1973
Manually operated gas valves Z21.15-1974
Trailer standard for coated flexible metal gas IAPMO
connectors for exterior use TSC
9-1972
Wrought seamless copper and ASTM
copper alloy tube B251-1971
Seamless copper pipe, standard ASTM
size B42-1972,
WW-P-377D-19-
62
Miscellaneous:
Air ducts 181-
--
1-
9-
72
Flame tests of flame-resistant 214-
fabrics --
1-
9-
71
Tube fittings for flammable 109-
and combustible fluids and --
1-
9-
72
refrigeration service.
LPG containers and accessories ASME, DOT
Pigtails, expansion coils, and 569-
flexible hose connectors for --
1-
9-
73
liquefied petroleum gas
Roof jacks for trailers 331-
coaches --
1-
9-
71
Relied valves and automatic Z21.22-1971
gas shutoff
devices for hot water supplu Z21.22a-1972
systems
Z21.22b-1974
Automatic gas ignition systems Z21.20-1971
& components
Z21.20a-1972
Z21.20b-1974
Automatic valves for gas Z21.21-1974
appliances
Gas appliance thermostats Z21.23-1971
Z21.23a-1972
Z21.23b-1972
Gas vents A131.2-1973 441-
--
1-
9-
73
Factory-built chemneys A131.1-1971 103-
--
1-
9-
71
Factory-built fireplaces A131.3-1971 127- GAL
--
1-
9-
71
Installation of oil buring A95.1-1974 NFPA No.
equipment 31-1974
Installation of gas
appliances, gas piping
in buildings Z223.1-1974 NFPA No.
54-1974
Resident type warm air heating NFPA No. 90
and air conditioning B-1973
Tests for flammability of 94--
plastic materials for parts in 1-
9-
74
devices and appliances.
Storage and handling of A 106.1-1974 NFPA No.
liquefied petroleum gas 58-1974
---------------------------------------------------------------------
208.703. Mimimum Standards.
Heating, cooling and fuel burning applicances and systems in mobile homes shall be free of defects and shall conform to applicable standards in the following able unless otherwise specified in this standard. (See 280.4.)
208.704. Fuel Supply Systems.
(a) LP-Gas system design and service line pressure.
(1) System shall be of the vapor-withdrawal type.
(2) Gas, at a pressure not over 14 inches water column (1/2 psi), shall be delivered from the system into the gas supply connection.
(b) LP-Gas Containers.
(1)Maximum capacity. No more than two comtainers having an individual water capacity of not more than 105 pounds (approximately 45 pounds LP-Gas capacity), shallbe installed on or in a compartment of any mobile home.
(2) Construction of containers. Containers shall be constructed and marked in accordance with specifications for LP-Gas Containers of the U.S. Department of Transportation (DOT) or the Rules for Construction of Unfired Pressure Vessels, Section VIII, Division 1, ASME Boiler and Pressure Vessel Code. ASME Containers shall have a design pressure of at least 312.5 psig. (i)Container supply systems shall be arranged for vapor withdrawal only. (ii)Container openings for vapor withdrawal shall be located in the vapor space when the container is in service or shall be provided with a suitable interal withdrawal tube which communicates with the vapor space in or near the higest point in the container when it is mounted in service position, with the vehicle on a level surface. Contatiners shall be permanently and legibly marked in a conspicuous manner on the outside to show the correct mounting position and the position of the service outlet connection. The method of mounting in place shall be such as to minimize the possibility of an incorrect positioning of the container.
(3)Location of LP-Gas Containers and Systems. (i)LP-Gas Containers shall not be installed, nor shall provisions be made for installing or storing any LP-Gas container, even temporarily, inside any mobile home except for listed, completely self-contained hand torches, lanterns, or similar equipment with containers habing a maximum water capacity of not more than 2-1/2 pounds (approximately on pound LP-Gas capacity). (ii) Containers, control valves, and regulation equipment, when installed, shall be mounted on the "A" frame of the mobile home, or installed in a compartment that is vaportight to this inside of the mobile home and acessible only from the outside. The compartment shall be ventilated at the top and bottom to facilitate diffusion of vapors. The compartment shall be ventilated with two vents having an aggreagte area of not less than two percent of the floor area of the compartment and shall open unrestricted to the outside atmosphere. The required vents shall be equally distributed between the floor and ceiling of the compartment. If the lower vent is located in the access door or wall, the bottom edge of the vent shall be flush with the floor level of the compartment. The top vent shall be located in the access door or wall with the bottom of the vent not more than 12 inches below the ceiling level of the compartment. All vents shall have an unrestricted discharge to the outside atmosphere. Access doors or panels of compartments shall not be equiped with locks or require special tools or knowledge to open. (iii) Permanent and removable fuel containers shall be securely mounted to prevent jarring loose, slipping or rotating and the fastenings shall be designed and constructed to withstand static loading in any direction equal to twice the weight of the tank and attachments when filled with fuel, using a safety factor of not less than four based on the ultimate strength of the material to be used.
(4) LP-Gas Container Valves and Accessories. (i) Valves in the assembly of a two-cylinder system shall be arranged so the replacement of containers can be made without shutting off the flow of gas to the appliance(s). This provision is not to be construed as requiring an automatic change-over device. (ii) Shutoff valves on the containers shall be protected as follows, in storage, and while being moved into final utilization by setting into a recess of the container to prevent possibility of their being struck if container is dropped upon a flat surface, or by ventilated cap or collar, fastened to the container, capable of withstanding a blow from any direction equivalent to that of a 30- pound weight dropped 4 feet. Construction shall be connected directly to the container shutoff valve outlets or mounted securely by means of a support bracket and connected to the container shutoff valve or valves with listed high pressure connections. If the container is permanently mounted the connector shall be required above or with a listed semi-rigid tubing connector.
(5) LP-Gas Safety Devices. (i) DOT containers shall be provided with safety relief devices as required by the regulations of the U.S. Department of Transportation. ASME containers shall be provided with relief valves in accordance with Subsection 221 of the Standard for the Storage and Handling of Liquefied Petroleum Gases (NPA NO 58-1974; ANSI Z106.1-1974). Safety relief valves shall have direct communication with the vapor space of the vessel. (ii) The delivery side of the gas pressure regulator shall be equipped with a safety relief device set to discharge at a pressure not less than two times and not more than three times the delivery pressure of the regulator. (iii) Systems mounted on the "A" frame assembly shall be so located that the discharge from the safety relief devices shall be into the open air and not less than three feet horizontally from any opening into the mobile home below the level of such discharge. (iv) Safety relief valves located with liquefied petroleum gas container compartments may be less than three feet from openings provided the bottom vent of the compartment is at the same level or lower than the bottom of any opening into the vehicle, or the compartment is not located on the same wall plane as the opening(s) and is at least two feet horizontally from such openings.
(6) LP-Gas System Enclosure and Mounting. (i) Housings and enclosures shall be designed to provide proper ventilation at least equivalent to that specified in 280-704(b)(3)(ii). (ii) Doors, hoods, domes, or portions of housings and enclosures required to be removed or opened for replacement of containers shall incorporated means for clamping them firmly in place and preventing them from working loose during transit. (iii) Provisions shall be incorporated in the assembly to hold the containers firmly in position and prevent their movement during transit. (iv) Containers shall be mounted on a substantial support or a base secured firmly to the vehicle chassis. Neither the container mor its support shall extend below the mobile home frame.
(c) Oil Tanks.
(1) Installation. Oil tanks and listed automatic pumps (oil lifters) installed for gravity flow of oil to heating equipment shall be installed so that the top of the tank is no higher than 8 feet above the appliance oil control and the bottom of the tank is not less than 18 inches above the appliance oil control and the bottom of the tank is not less than 18 inches above the appliance oil control.
(2) Auxiliary Oil Storage Tank. Oil supply tanks affixed to a mobile home shall be so located as to require filling and draining from the outside and shall be in a place readily available for inspection. If the fuel supply tank is located in a compartment of a mobile home, the compartment shall be ventilated at the bottom to permit diffusion of vapors and shall be insulated from the structural members of the body. Tanks so installed shall be provided with an outside fill and vent pipe and an approved liquid level gage.
(3) Shutoff Valve. A readily accessible, approved manual shutoff valve shall be installed at the outlet of an oil supply tank. The valve shall be installed to close against the supply.
(4) Fuel Oil Filters. All oil tanks shall be equipped with an approved oil filter or strainer located downstream from the tank shutoff valve. The fuel oil filter or strainer shall contain a sump with a drain for the entrapment of water.
280.705. Gas Piping Systems.
(a) General. The requirements of this Section shall govern the installtion of all fuel gas piping attached to any mobile home. The gas piping supply system shall be designed for a pressure not exceeding 14 inch water column (1/2 psi) and not less than 7 inch water column (1/4 psi). The manufacturer shall indicate in his written installation instructions the design pressure limitations for safe and effective operation of the gas piping system. None of the requirements listed in this section shall apply to the piping supplied as a part of an appliance. All exterior openings around piping. ducts, plenums or vents shall be sealed to resist the entrance of rodents.
(b) Materials. All materials used for the installation, extension, alteration, or repair of any gas piping system shall be new and free from defects or internal obstructions. It shall not be permissible to repair defets in gas piping or fittings. Inferior or defective materials shall be removed and replaced with acceptable material. The system shall be made of materials having a melting point of not less than 1,4505<>oF, except as provided in 280.705(e). They shall consist of one or more of the materials described in 280.705(b)(1) through (4).
(1) Steel or wrought-iron pipe shall comply with ANSI Standard B36.10-1970 for Wrought-Steel and Wrought-Iron Pipe. Threaded brass pipe in iron pipe sizes may be used. Threaded brass pipe shall comply with Standard Sizes and Specifications for Seamless Red Brass Pipe (ASTM B43-66).
(2) Fittings for gas piping shall be wrought iron, malleable iron, steel, or brass (containing not more tha 75 percent copper).
(3) Copper tubing shall be annealed type, Grade K or L, conforming to the Specifications for Seamless Copper Water Tube (ASTM B88-72), or shall comply with the Specifications for Seamless Copper Tube for Air Conditioning and Refrigeration Field Services, ASTM B280-73. When used on systems designed for natural gas, such tubing shall be internally tinned.
(4) Steel tubing shall have a minimum wall thickness of 0.032 inch for tubing of 1/2 inch diameter and smaller and 0.049 inch for diameters 1/2 inch or larger. Steel tubing shall be constructed in accordance with ASTM Specification for Electric-Welded Coiled Steel Tubing for Gas and Fuel Oil Lines (ASTM A539- 73), and shall be externally corrosion protected.
(c) Piping design. Each mobile home requiring fuel gas for any purpose shall be equiped with a fuel gas piping system that is designed for LP-Gas only or with a natural gas piping system acceptable for LP-Gas.
(1) Where fuel gas piping is to be installed in both portions of an expandable or multiple unit mobile home, the design and construction of the crossover shall be as follows: (i) There shall be only one point of crossover which shall be readily accessible from the exterior of the mobile home. (ii) The connector between units shall be a listed type for exterior use, sized in accordance with 280.705(d). (ii) The connection shall be made by a listed "quick disconnect" device which shall be designed to provide a postive seal of the supply side of the gas system when such device is separated. (iv) The flexible connector and "quick disconnect" device shall be provided with protection from mechanical and imnpact damage and located to minimize the possibility of tampering. (v) Suitable protective coverings for the "quick disconnect" device, when separated, shall be permanently attached to the device or flexible connector. (vi) A 3-inch by 1-3/4 inch minimum size tag made of etched, metal-stamped or embossed brass, stainless steel, anodized or alclade aluminum not less than 0.020 inch thick or other approved material (e.g., 0.005 inch plastic laminates) shall be permenently attached on the exterior wall adjacent to the access to the "quick disconnect" device. Each tag shall be legibly inscribed with the following information using letters no smaller than 1/4 inch high:
DO NOT USE TOOLS TO SEPARATE THE "QUICK-DISCONNECT" DEVICE.
(d) Gas Pipe Sizing. Gas piping systems shall be sized so that the pressure drop to any appliance inlet connection from any gas supply connection, when all appliances are in operation at maximum capacity, is not more than 0.5 inch water column as determined on the basis of test, or in accordance with the following Table. When determilning gas pipe sizing in the table, gas shall be assumed to have a specific gravity of 0.65 and rated at 1000 B.T.U. per cubic foot. The natural gas supply connection(s) shall not be less than the size of the gas piping but shall not be smaller that 3/4 inch nominal pipe size.
(e) Joints for Gas Pipe. All pipe joints in the piping system, unless welded or brazed, shall be threaded joints that comply with ANSI Standard Pipe Threads (Except Dryseal) D2-1-1968, Right and left nipples or couplings shall not be used. Unions, if used, shall be of ground joint type. The material used for welding or breaking pipe connections shall have a melting temperature in excess of 1,000<>oF.
(f) Joints for Tubing.
(1) Tubing joints shall be made with either a single or double flare of 45 degrees in accordance with S.A.E. Standard J533A or with other listed vibration-resistant fittings, or joints may be brazed with material having a melting point exceeding 1,000<>oF. Metallic ball sleeve compresion-type tubing fittings shall not be used.
Iron Pipe Sizes
Length in Feet
I.D. 10 20 30 40 50 60 70 80 90 100
1/4' 43 29 24 20 18 16 15 14 13 12
3/8' 95 65 52 45 40 36 33 31 29 27
1/2' 175 120 97 82 73 66 61 57 53 50
3/4' 360 250 200 170 151 138 125 118 110 103
1' 680 465 375 320 285 260 240 220 215 195
Tubing
Length in Feet
O.D. 10 20 30 40 50 60 70 80 90 100
3/8' 27 18 15 13 11 10 9 9 8 8
1/2' 56 38 31 26 23 21 19 18 17 16
5/8' 113 78 62 53 47 43 39 37 34 33
3/4' 197 136 109 93 83 75 69 64 60 57
7/8' 280 193 155 132 117 106 98 91 85 81
Part II
Maximum Capacity of Different Sizes of Pipe and Tubing in Thousands of BTUs per
Hour of Undiluted Liquefied Petroleum Gas
Based on a Maximum Pressure Drop of 1/2 Inch Water Column
Iron Pipe
Length in Feet
I.D. 10 20 30 40 50 60 70 80 90 100
1/4' 67 46 37 31 28 25 23 21 20 19
3/8' 147 101 81 70 62 56 51 48 45 42
1/2' 275 189 152 129 114 103 96 89 83 78
3/4' 567 363 315 267 237 217 196 185 173 162
1' 1071 732 590 504 448 409 378 346 322 307
Tubing
Length in Feet
O.D. 10 20 30 40 50 60 70 80 90 100
3/8' 39 26 21 19 -- -- -- -- -- --
1/2' 92 62 50 41 37 35 31 29 27 26
5/8' 199 131 107 90 79 72 67 62 59 55
3/4' 329 216 181 145 131 121 112 104 95 90
7/8' 501 346 277 233 198 187 164 155 146 138
(2) Steel tubing joints shall be made with a double-flare in accordance with SAE Standard J 533A.
(g) Pipe Joint Compound. Screw joints shall be made up tight with listed pipe joint compound, insoluble in liquefied petroleum gas, and shall be applied to the male threads only.
(h) Concealed Tubing. Tubing shall no be run inside walls, floors, partitions, or roofs. Where tubing passes through walls, floors, partitions roofs, or similar installations, such tubing shall be protected by the use of weather resistant grommets that shall snugly fit both the tubing and the hole through which the tubing passes.
(i) Concealed Joints. Piping or tubing joints shall not be located in any floor, wall partition, or similar concealed construction space.
(j) Location of gas supply connection.
(1) For LP-Gas-only systems the supply connection shall be located at the 'A' frame, container recess, or in the rear half of the total length of the mobile home and within 24 inches from the left (road) side wall, and should be as close as practicable to a point 30 feet from the front of the mobile home.
(2) For combination LP-Gas and natural gas systems, the natural gas supply connection shall be located under the rear half of the total length of the mobile home and within 24 inches of the left (road) side wall and be located as close as practicable to a point 30 feet from the front of the mobile home. The natural gas supply connection shall not be located beneath any exit door. An additional connection, if used, shall be located at the 'A' frame. The system shall be sized to provide adequate capacity from either supply connection for natural gas.
(k) Identification of gas supply connections. Each mobile home shall have permanently affixed to the exterior skin at or near each gas supply connection or the end of the pipe, a tag of 3 inches by 1-3/4 inches minimum size, made of etched, metal-stamped or embossed brass, stainless steel, anodized or alclade aluminum not less than 0.020 inch thick, or other approved material (e.g., 0.005 inch plastic laminates), which reads (as appropriate) in accordance with one of the following label designs depending upon the fuel used. The connector capacity indicated on this tag shall be equal to or greater than the total Btuh rating of all intended gas appliances.
(l) Gas supply connectors.
(1) LP-Gas. A listed LP-Gas flexible connector conforming to the UL Standard for Pigtails, Expansion Coils and Flexible Hose Connectors for LP-Gas (UL 569- 1973) or equal shall be supplied when the fuel gas piping system is designed for the use of LP-Gas and cylinder(s) and regulator(s) are suppplied.
(2) Appliance connections. All gas burning appliances shall be connected to the fuel piping. Materials as provided in 280.705(b) or listed appliance connectors shall be used. Listed appliance connectors when used shall not run through walls, ceilings or partitions. Connectors of aluminum shall not be used outdoors. A mobile home containing an LPG or combination LP-natural-gas-system may be provided with a gas outlet to supply exterior appliances when installed in accordance with the following: (i) No portion of the completed installation shall project beyond the wall of the mobile home. (ii) The outlet shall be provided with an approved 'quick-disconnect' device, which shall be designed to provide a positive seal on the supply side of the gas system when the appliance is disconnected. A shutoff valve shall be installed immediately upstream of the quick-disconnect device. The complete device shall be provided as part of the original installation. (iii) Protective caps or plugs for the 'quick disconnect' device, when disconnected, shall be permanently attached to the mobile home adjacent to the device. (iv) A tag shall be permanently attached to the outside of the exterior wall of the home home as close as possible to the gas supply connection. The tag shall indicate the type of gas and the Btuh capacity of the outlet and shall be legibly incribed as follows:
THIS OUTLET IS DESIGNED FOR USE WITH GAS PORTABLE APPLIANCES WHOSE TOTAL INPUT DO NOT EXCEED ______ BTUH. REPLACE PROTECTIVE COVERING OVER CONNECTOR WHEN NOT IN USE.
(3) Valves. A shutoff valve shall be installed in the fuel piping at each gas appliance inside the mobile home structure, upstream of the union or connector in addition the any valve on the appliance and so arranged to be accessible to permit servicing of the appliance and removal of its components, and for shut-off in case of emergency. The shutoff valve shall be located within 6 feet of a cooking appliance and within 3 feet of any other appliance. A shutoff valve may serve more than one appliance if located as required above. Shutoff valves used on connection with gas piping shall be of a type designed and listed for use in LP-Gas.
(4) Gas Piping System Openings. All openings in the gas piping system shall be closed gas-tight with threaded pipe plugs or pipe caps.
(5) Electrical Ground. Pipe couplings and unions shall be used to join sections of threaded piping. Right and left nipples or couplings shall not be used.
(6) Couplings. Pipe couplings and unions shall be used to join sections of threaded piping. Right and left nipples or couplings shall not be used.
(7) Hangers and Supports. All gas piping shall be adequately supported by galvanized or equivalently protected metal straps or hangers at intervals of not more than 4 feet, except where adequate support and protection is provided by structural members. Solid-iron-pipe gas supply connection(s) shall be rigidly anchored to a structural member within 6 inches of the supply connection(s).
(8)Testing for Leakage. (i) Before appliances are connected, piping systems shall stand a pressure of at least six inches mercury or three PSI gage for a period of not less than ten minutes without showing any drop in pressure. Pressure shall be measured with a mercury manometer or slope gage calibrated so as to be read in increments of not greater than one-tenth pound, or an equivalent device. The source of normal operating pressure shall be isolated before the pressure tests are made. Before a test is begun, the temperature of the ambient air and of the piping shall be approximately the same, and constant air temperature be maintained throughout the test. (ii) After appliances are connected, the piping system shall be pressurized to not less than 10 inches nor more than 14 inches water column and the appliance connections tested for leakage with soapy water or bubble solution.
280.706. Oil Piping Systems.
(a) General. The requirements of this section shall govern the installation of all liquid fuel piping attached to any mobile home. None of the requirements listed in this Section shall apply to the piping in the appliance(s).
(b) Materials. All materials used for the installation extension, alteration, or repair, of any oil piping systems shall be new and free from defects or internal obstructions. The system shall be made of materials having a melting point of not less than 1,450° F, except as provided in 280.706(d) and (e). They shall consist of one or more of the materials described in 2890.706(b)(1) through(4). (1) Steel or wrought-iron pipe shall comply with American National Standard For Wrought-Steel or Wrought-Iron Pipe, R36.10-1970. Threaded copper or brass pipe in iron pipe sizes may be used. (2) Fittings for oil piping shall be wrought iron, malleable iron, steel, or brass (containing not more than 75 percent copper). (3) Copper tubing shall be annealed type, Grade K or L conforming to the Specifications for Seamless Copper Water Tube (ASTM B88-72), or shall comply with the specifications for Seamless Copper Tube for Air Conditioning and Refrigeration Field Service, ASTM B280-73. (4) Steel tubing shall have a minimum wall thickness of 0.032 inch for diameters up to 1/2-inch and 0.049 inch for diameters 1/2-inch and larger. Steel tubing shall be constructed in accordance with the Specification for Electric-Resistance Welded Coiled Steel Tubing for Gas and Fuel Oil Lines (ASTM A539-73) and shall be externally corrosion protected.
(c) Size of Oil Piping. The minimum size of all fuel tank piping connecting outside tanks to the appliance shall be no smaller than 3/80-inch OD copper tubing or 1/4-inch IPS. If No. 1 fuel oil is used with a listed automatic pump (fuel lifter), copper tubing shall be sized as specified by the pump manufacturer.
(d) Joints for Oil Piping. All pipe joints in the piping system, unless welded or brazed, shall be threaded joints which comply with American National Standard for Pipe Threads (Except Dryseal), B2.1-1968. The material used for brazing pipe connections shall have a melting temperature in excess of 1,000° F.
(e) Joints for Tubing. Joints in tubing shall be made with either a single or double flare of the proper degree, as recommended by the tubing manufacturer, by means of listed tubing fittings, or brazed with materials having a melting point in excess of 1,000° F.
(f) Pipe joint compound. Threaded joints shall be made up tight with listed pipe joint compound which shall be applied to the male threads only.
(g) Couplings. Pipe couplings and unions shall be used to join sections of threaded pipe. Right and left nipples or couplings shall not be used.
(h) Grade of piping. Fuel oil piping installed in conjunction with gravity feed systems to oil heating equipment shall slope in a gradual rise upward from a central location to both the oil tank and the appliance in order to eliminate air locks.
(i) Strap hangers. All oil piping shall be adequately supported by galvanized or equivalently protected metal straps or hangers at intervals of not more than 4 feet, except where adequate support and protection is provided by structural members. Solid-iron-pipe oil supply connection(s) shall be rigidly anchored to a structural member within 6inches of the supply connection(s). (continued)