PURPOSE: This rule sets forth the inspection procedure to be followed by all authorized inspectors of school buses which are equipped with liquefied propane gas carburetion. The annual inspection period, July through August, is established and the inspection is to be performed by an installer of liquefied propane gas registered with the Division of Weights and Measures, Department of Agriculture. PUBLISHER’S NOTE: The secretary of state has determined that the publication of the entire text of the material which is incorporated by reference as a portion of this rule would be unduly cumbersome or expensive. Therefore, the material which is so incorporated is on file with the agency who filed this rule, and with the Office of the Secretary of State. Any interested person may view this material at either agency’s headquarters or the same will be made available at the Office of the Secretary of State at a cost not to exceed actual cost of copy reproduction. The entire text of the rule is printed here. This note refers only to the incorporated by reference material.

1. (1) A school bus equipped with liquefied propane (LP) gas carburetion shall be inspected annually during the months of July or August by a person who is an official installer, registered with the Division of Weights and Measures, Department of Agriculture.

2. (2) The inspection must be performed following the detailed procedure for school buses set forth.

   1. (A) Containers.

      1. 1. American Society of Mechanical

Engineers’ (ASME) containers shall be constructed for at least a two hundred fifty (250) pounds per square inch gauge (psig) design pressure and installed in accordance with paragraph (2)(A)4.

1. 2. Installations made after February 11,

1983 shall include an automatic eighty percent (80%) stop fill device.

1. 3. All container valves and fittings must

be protected by means of a heavy gauge, metal guard, (minimum seven (7) gauge), as supplied by the tank manufacturer. This guard must be securely attached to the tank with a minimum of two (2) bolted connections, using three-eighths inch (3/8") grade five (5) bolts (or the guard may be welded directly to the tank at the tank manufacturer’s option). These valves, fittings and gauges must also be protected from road debris by using mud flaps or metal shields installed in front of the container. A mud flap or metal shield shall be installed to the rear of fuel container if container is three feet (3') or less from rear wheels of bus.

1. 4. LP-gas fuel containers used on pas-

senger-carrying vehicles shall not exceed two hundred (200) gallons aggregate water capacity. (No single tank to exceed one hundred (100) gallon water capacity.) The tank(s) shall be mounted on either side of the bus, each on the outside frame rail and between the axles.

1. 5. If the fuel container must be installed

twelve inches (12") or closer to the engine or exhaust system, it shall be entirely shielded against the source of direct heat by means of a metal shield. (The main frame rail shall be considered to be a partial heat shield.)

1. 6. After the effective date of this rule all

LP gas tanks being installed or reinstalled on school buses shall incorporate strap-type brackets at the frame rail with no bolts passing through the frame rail. Brackets may either encircle the tank and frame rail or encircle only the frame rail and attach to the manufacturer’s tank brackets when the tank is so equipped. If the brackets encircle the tank they must be steel bands of not less than three-eighths inch (3/8") thickness and not less than two inches (2") in width. No less than two (2) brackets should be used on tanks up to thirty-six inches (36") in length. Not less than three (3) brackets should be used on tanks longer than thirty-six inches (36").

1. 7. The clamps that encircle the frame

rail shall consist of straight bolts and backup plates (no U-bolts to be used). The backup plates used must be steel and have a minimum thickness of three-eighths inch (3/8") and a minimum width of two inches (2").

1. 8. A minimum of two (2) bolts per

bracket using five-eighths inch (5/8") grade eight (8) bolts must be used to attach the bracket to the main frame. A minimum onehalf inch (1/2") grade five (5) bolt must be used to secure the strap to the tank.

1. 9. After the February 11, 1983 all LP

gas tanks being installed or reinstalled may be on the left or right side of the vehicle. However, if it is mounted on the right side, the container vessel shall not be less than three feet (3') from the passenger entrance door.

1. 10. Containers shall be installed with as

much road clearance as practicable but not less than seven inches (7") on vehicles having a wheelbase of one hundred twenty-seven inches (127") or less nor less than nine inches (9") on vehicles having a wheelbase of more than one hundred twenty-seven inches (127"). This clearance shall be measured when the vehicle is under full rated load and is standing on a flat surface. It shall be measured to the bottom of the container or to the lowest fitting, support or attachment on the container or container housing, whichever is lower under full rated load of the bus. But in no case, shall the bottom of the tank be lower than the lowest point of the vehicle.

1. 11. Where remote-fill connections are

used, double back pressure check valves shall be installed both at the tank and at the remote-fill location, and a shutoff valve or fitting with a number fifty-four (#54) drill size hole shall be installed in the eighty percent (80%) tank outage connection, in addition to the (fixed liquid level) gauge at the remote location.

1. (B) Container Safety Relief Valve Pipeaway. After the effective date of this rule, the relief valve discharge shall be to a flushmounted (recessed) fitting mounted in the skirt of the bus below the rub rail. Prior to the effective date of this rule flush-mounted (recessed) is considered to be not protruding past the rub rail. After the effective date of this rule flush-mounted (recessed) is considered to be not protruding past the bus body. This recessed fitting shall provide that the discharge of the relief valve be directed to not more than forty-five degrees (45°) of vertical. A means shall be provided (such as a loose fitting cap) to minimize the possibility of the entrance of water or dirt into the pipe. The protecting means shall remain in place except when the relief valve operates and be designed to close automatically. In this event, it shall permit the relief valve to operate at sufficient capacity. This fitting shall also be constructed so as to prevent tampering and entrance of road debris by use of wire mesh. Safety relief valve discharge lines shall be metallic and have a melting point over one thousand five hundred degrees Fahrenheit (1,500°F) (eight hundred sixteen degrees Celsius (816°C)). Relief valve adaptors installed directly in the relief valve to deflect the flow upward shall be metallic and have a melting point over seven hundred degrees Fahrenheit (700°F). Discharge lines and adaptors are not to be reduced in size from the inside diameter of the relief valve and are not to be less than one inch (1") inside diameter. Piping from the relief valve to the outside of the bus shall not be more than fortyeight inches (48") in length. The relief valve discharge line shall be able to withstand the pressure from the relief valve discharge and remain vapor tight when the relief valve is in full open position.

2. (C) Piping, Hose and Fittings.

   1. 1. Pipe shall be wrought iron or steel

(black or galvanized), brass or copper and shall comply with the following:

1. A. Wrought iron pipe; ANSI B36.10-

1979 Welded and Seamless Wrought Steel Pipe;

1. B. Steel pipe; ASTM A53-81a Welded

and Seamless Steel Pipe;

1. C. Steel pipe; ASTM A106-80

Seamless Carbon Steel Pipe for High Temperature Service;

1. D. Steel pipe; ASTM A120-81 Black

and Hot Dipped Zinc-Coated (Galvanized) Welded and Seamless Steel Pipe for Ordinary Uses;

1. E. Brass pipe; ASTM B43-80

Seamless Red Brass Pipe; and

1. F. Copper pipe; ASTM B42-82

Seamless Copper Pipe.

1. 2. For LP gas vapor in excess of one

hundred twenty-five (125) psig or for LP gas liquid, the pipe shall be Schedule 80 or heavier. For LP gas vapor at pressures of one hundred twenty-five (125) psig or less, the pipe shall be Schedule 40 or heavier.

1. 3. Tubing shall be steel, brass or copper

and shall comply with the following:

1. A. Steel tubing; ASTM A539-79

Electric-Resistance Welded Coiled Steel Tubing for Gas and Oil Lines with a minimum wall thickness of 0.049 inches;

1. B. Copper tubing; Type K or L,

ASTM B88-81 Seamless Copper Water Tube;

1. C. Copper tubing; ASTM B280-80

Seamless Copper Tube for Air Conditioning and Refrigeration Field Service; and

1. D. Brass tubing; ASTM B135-82

Seamless Brass Tube.

1. 4. Cast iron pipe fittings, such as ells,

tees, crosses, couplings, unions, flanges or plugs, shall not be used. Fittings shall be steel, brass, copper, malleable iron or ductile iron and shall comply with the following:

1. A. Pipe joints in wrought iron, steel,

brass or copper pipe may be screwed, welded or brazed. Tubing joints in steel, brass or copper tubing may be flared or brazed. Fittings may be flared, soldered or brazed.

1. (I) Fittings used with liquid LP gas

or with vapor LP-gas at operating pressures over one hundred twenty-five (125) psig shall be suitable for a working pressure of two hundred fifty (250) psig.

1. (II) Fittings for use with vapor LP

gas at pressures in excess of five (5) psig and not exceeding one hundred twenty-five (125) psig shall be suitable for a working pressure of one hundred twenty-five (125) psig; and

1. B. Brazing and soldering filler material

shall have a melting point exceeding one thousand degrees Fahrenheit (1,000°F).

1. 5. Hose, hose connections and flexible

connectors used for conveying LP-gas liquid or vapor at pressures in excess of five (5) psig shall be fabricated of materials resistant to the action of LP-gas both as liquid and vapor and be of wire braid reinforced construction. The 2 CSR 90-10

wire braid shall be of stainless steel. The hose shall comply with the following:

1. A. Hose shall be designed for a min-

imum bursting pressure of one thousand seven hundred fifty (1,750) psig (three hundred fifty (350) psig working pressure) and shall be marked with “LP-gas” or “LPG” and with the working pressure in psig at not greater than ten foot (10') intervals; and

1. B. Hose assemblies after the applica-

tion of connections, shall have a design capability of withstanding a pressure of not less than seven hundred (700) psig. If a test is made, the assemblies shall not be leak tested at pressures higher than the work pressure (three hundred fifty (350) psig minimum) of the hose.

1. 6. Hose used for vapor service at five

1. (5) psig or less shall be constructed of materials resistant to the action of LP gas.

   1. 7. Hose in excess of five (5) psig service

pressure and quick connectors shall be approved.

1. (D) Pipe and Hose Installation.

   1. 1. The piping system shall be designed,

installed, supported and secured in a manner as to minimize the possibility of damage due to expansion, contraction, vibration, strains or wear and to preclude any working loose while in transit. Supports should be installed as necessary to insure that segments of liquid hose do not extend without support beyond twenty-four inches (24").

1. 2. Piping shall be installed in a protect-

ed location, under the vehicle and below any insulation or false bottom, fastenings and protection shall be so as to prevent abrasion or damage due to vibration. At points where piping passes through structural members, a rubber grommet or bulkhead shall be installed to prevent chafing.

1. 3. Exposed parts of the piping system

shall either be of corrosion-resistant material or adequately protected against exterior corrosion.

1. 4. Piping systems, including hose, shall

be tested and proven free of leaks at not less than normal operating pressure.

1. 5. After the effective date of this rule,

all hydrostatic relief valves being installed or reinstalled shall be installed in each section of piping (including hose) in which liquid LP gas can be isolated between shutoff valves so as to relieve to a safe atmosphere the pressure which could develop from the trapped liquid. This hydrostatic relief valve shall have a pressure setting not less than four hundred (400) psig or more than five hundred (500) psig.

1. (E) Equipment Installation.

   1. 1. Installation shall be made in accor-

dance with the manufacturer’s recommendations and, in the case of listed or approved equipment, it shall be installed in accordance with the listing or approval.

1. 2. Equipment installed on a vehicle as

part of the LP gas system shall be considered a part of the vehicle and shall be installed so as not to interfere with, nor be damaged by the movement of other mechanical parts in the normal operation of the vehicle.

1. 3. The gas regulator and the carburetor

shall be installed as follows:

1. A. Approved automatic pressure

reducing equipment, properly secured, shall be installed between the fuel supply container and the carburetor to regulate the pressure of the fuel delivered to the carburetor; and

1. B. An approved automatic shutoff

valve shall be provided in the fuel system in compliance with paragraph (2)(E)8.

1. 4. Vaporizers shall be securely fastened

in position.

1. (F) Carburetion Equipment.

   1. 1. Carburetion equipment shall comply

with this subsection or shall be designed, fabricated, tested and marked using criteria which incorporate and investigation to determine that they are safe and suitable for the proposed service, are recommended for that service by the manufacturer and are acceptable to the authority having jurisdiction.

1. 2. Carburetion systems must remain

intact as a total unit unless a component is removed for repair or replacement. If use of carburetion system is discontinued, system must be removed in total with no LP gas equipment remaining on vehicle. If a component is removed from the system for repair or replacement, gas supply shall be blocked off at the fuel container supply valve with an approved threaded cap or plug.

1. 3. Vaporizers shall be fabricated of

materials suitable for LP gas service and resistant to the action of LP gas under service conditions. These vaporizers shall be designed and approved for engine fuel service and shall comply with the following: The vaporizer proper, any part of it or any devices used with it which may be subjected to container pressure, shall have a design pressure of at least two hundred fifty (250) psig and shall be plainly and permanently marked at a readily visible point with a design pressure of the fuel containing portion in psig.

1. 4. The vaporizer shall not be equipped

with a fusible plug.

1. 5. Each vaporizer shall have a valve, or

suitable plug located at or near the lowest portion of the section occupied by the water or other heating liquid to permit substantially complete drainage. The engine cooling system drain or water hoses may serve this purpose, if effective.

1. 6. Engine exhaust gases may be used as

a direct source of heat to vaporize the fuel if the materials of construction of those parts of the vaporizer in contact with the exhaust gases are resistant to corrosion from these gases and if the vaporizer system is designed to prevent pressure in excess of two hundred (200) psig.

1. 7. Devices which supply heat directly to

the fuel container shall be equipped with an automatic device to cut off the supply of heat before the pressure in the container reaches two hundred (200) psig.

1. 8. The regulator shall be approved and

can either be part of the vaporizer unit or a separate unit.

1. 9. An approved automatic shutoff valve

shall be provided in the fuel system at some point ahead of the inlet of the gas regulator. The valve shall prevent flow of fuel to the carburetor when the engine is not running even if the ignition switch is in the “on” position. Atmospheric type regulators (zero governors) shall not be considered as automatic shutoff valves for this purpose.

1. 10. Fuel filters, if used, shall be

approved and can be either a separate unit or part of a combination unit.

1. 11. Dual fuel systems (gasoline/

propane) shall use approved gasoline lockoff valves. Each valve shall be installed with steel line from carburetor to a point below intake manifold and away from exhaust manifold. Electric fuel pumps are not considered an approved gasoline lockoff valve.

1. (3) It shall be the responsibility of the school to properly train all persons operating the LP gas dispenser.
2. (4) The registered installer making the inspection shall be required to complete the school bus inspection report in triplicate. One
3. (1) copy is to be filed with the school district, one (1) is to be sent to the Division of Weights and Measures, P.O. Box 630, Jefferson City, MO 65102, and one (1) copy to remain with the installer for his/her files. The school bus inspection report will be furnished by the Division of Weights and Measures upon written request.
4. (5) A registered installer completing the required annual inspection or making the original installation of liquefied propane gas carburetion on a school bus must be in compliance with 2 CSR 90-10.040 and this rule.
5. (6) The Division of Weights and Measures, Department of Agriculture will forward monthly during July, August and September, a report to the Department of Elementary and Secondary Education detailing conditions existing on inspected buses and recommendations made to the school district or bus owner for corrections if required.

AUTHORITY: section 323.020, RSMo 1986.* Original rule filed Oct. 13, 1982, effective Feb. 11, 1983. Amended: Filed May 2, 1985, effective Sept. 27, 1985. Amended: Filed March 3, 1989, effective June 29, 1989.

*Original authority: 323.020, RSMo 1947.