# Auto repair source capture system



## klarenbeek (Sep 27, 2010)

Would a car exhaust source capture system fall under the category of a hazardous exhaust system covered by IMC section 510? Most of the section seems to be geared to systems with flammable vapors, but car exhaust, while not flammable, would definitely be included in the health hazard ratings covered in section 510.2.  The specific question is a contractor is designing an underground system and wants to use PVC duct in the underground portion, but it does not meet the duct construction requirements of section 510.8.  Any input would be appreciated.


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## globe trekker (Sep 28, 2010)

From the `06 IMC - Section 510.2:

"Nonmetallic ducts utilized in systems exhausting nonflammable corrosive fumes or

vapors shall be listed and labeled.    Nonmetallic duct shall have a flame spread index

of 25 or less and a smoke-developed index of 50 or less, when tested in accordance

with ASTM E 84. Ducts shall be approved for installation in such an exhaust system."

Ask the contractor to provide you with documentation that the pvc is an approved

material meeting the requirements of this code section, ...otherwise, "No way Jose!"

.


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## Dr. J (Sep 28, 2010)

A "Hazardous Exhaust" is required where "_in the absence of such exhaust systems and under normal operating conditions, have the potential to create one of the following conditions: ... _  I think you can easily make the point that if it were not for the exhaust system, operating vehicles inside a building would create one of the conditions listed.  Therefore the letter of the code would mean that it is a Hazardous Exhaust System, and the 25/50 requirements apply.

In addition, vehicle exhaust contains unburned hydrocarbons and these will settle out in the low points of the exhaust system.  The exhaust system should be compatible with hydrocarbons, and not soften/dissolve/melt in their presence, like many plastics would.  Thus this is a poor choice, and even if they appealed to your approval authority as AHJ, you should not give it.


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## klarenbeek (Sep 28, 2010)

Thats the way we were leaning, thanks for the input!


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## skipharper (Sep 29, 2010)

502.13 Public garages.

Mechanical exhaust systems for public garages, as required in Chapter 4, shall operate continuously or in accordance with Section 404.

502.14 Motor vehicle operation.

In areas where motor vehicles operate, mechanical ventilation shall be provided in accordance with Section 403. Additionally, areas in which stationary motor vehicles are operated shall be provided with a source capture system that connects directly to the motor vehicle exhaust systems.

Exceptions:

1. This section shall not apply where the motor vehicles being operated or repaired are electrically powered.

2. This section shall not apply to one- and two-family dwellings.

3. This section shall not apply to motor vehicle service areas where engines are operated inside the building only for the duration necessary to move the motor vehicles in and out of the building.

[F] 502.15 Repair garages.

Where Class I liquids or LP-gas are stored or used within a building having a basement or pit wherein flammable vapors could accumulate, the basement or pit shall be provided with ventilation designed to prevent the accumulation of flammable vapors therein.

[F] 502.16 Repair garages for natural gas- and hydrogen-fueled vehicles.

Repair garages used for the repair of natural gas- or hydrogen-fueled vehicles shall be provided with an approved mechanical ventilation system. The mechanical ventilation system shall be in accordance with Sections 502.16.1 and 502.16.2.

Exception: Where approved by the code official, natural ventilation shall be permitted in lieu of mechanical ventilation.

[F] 502.16.1 Design.

Indoor locations shall be ventilated utilizing air supply inlets and exhaust outlets arranged to provide uniform air movement to the extent practical. Inlets shall be uniformly arranged on exterior walls near floor level. Outlets shall be located at the high point of the room in exterior walls or the roof.

 Ventilation shall be by a continuous mechanical ventilation system or by a mechanical ventilation system activated by a continuously monitoring natural gas detection system, or for hydrogen, a continuously monitoring flammable gas detection system, each activating at a gas concentration of 25 percent of the lower flammable limit (LFL). In all cases, the system shall shut down the fueling system in the event of failure of the ventilation system.

 The ventilation rate shall be at least 1 cubic foot per minute per 12 cubic feet [0.00138 m3/(s • m3)] of room volume.

[F] 502.16.2 Operation.

The mechanical ventilation system shall operate continuously.

Exceptions:

1. Mechanical ventilation systems that are interlocked with a gas detection system designed in accordance with the International Fire Code.

2. Mechanical ventilation systems in garages that are used only for the repair of vehicles fueled by liquid fuels or odorized gases, such as CNG, where the ventilation system is electrically interlocked with the lighting circuit.

And for the exhaust you use:

SECTION 512

SUBSLAB SOIL EXHAUST SYSTEMS

512.1 General.

When a subslab soil exhaust system is provided, the duct shall conform to the requirements of this section.

512.2 Materials.

Subslab soil exhaust system duct material shall be air duct material listed and labeled to the requirements of UL 181 for Class 0 air ducts, or any of the following piping materials that comply with the International Plumbing Code as building sanitary drainage and vent pipe: cast iron; galvanized steel; brass or copper pipe; copper tube of a weight not less than that of copper drainage tube, Type DWV; and plastic piping.

512.3 Grade.

Exhaust system ducts shall not be trapped and shall have a minimum slope of one-eighth unit vertical in 12 units horizontal (1-percent slope).

512.4 Termination.

Subslab soil exhaust system ducts shall extend through the roof and terminate at least 6 inches (152 mm) above the roof and at least 10 feet (3048 mm) from any operable openings or air intake.

512.5 Identification.

Subslab soil exhaust ducts shall be permanently identified within each floor level by means of a tag, stencil or other approved marking.


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## JMORRISON (Sep 29, 2010)

A subslab soil exhaust is for reducing radon gas issues.


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## skipharper (Sep 29, 2010)

Very true, one of many uses!!


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## klarenbeek (Sep 29, 2010)

The subslab soil exhaust would not apply here.  That's intended for radon (or if for whatever reason something else is getting ehxausted out of the soil).  This is an exhaust system for car exhaust fumes (taken from above ground). The system could also run overhead, but the designer, for building layout purposes, wants to run it underground. No fumes are being pulled from the soil below the floor slab, so its not subslab soil exhaust.


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## skipharper (Sep 30, 2010)

Your are right, I stand corrected!!


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