406 SE EVERETT MALL WAY KS AUTO REPAIR 2016-09-20

EXHAUST SYSTEMS , w Ciass I flammable liquids are processed or handled. Uncontaminated air, such as outdoor air or transfer air, must be distributed to dilute and disperse vapors over the entire solid floor area and then discharge them to a safe location outside the building. A ventila- tion rate of 1 cfm/ftZ [0.00508 m3/(s • mz)] is required. 502.13 Public garages. Mechanical exhaust systems for pub- lic garages, as required in Chapter 4, shall operate continu- ously or in accordance with Section 404. •:• This section applies to parking garages and does not apply to repair garages. As a means of conserving energy, ventilation systems for enclosed public park- ing garages are allowed to modulate between full capacity and the minimum capaciry specified in Sec- tion 404.2. This modulating operation must use approved detection devices that are capable of detecting the operation of vehicles in the garage. This section is intended to apply to parking garages for vehicles such as automobiles, buses and fleet vehi- cles (see commentary, Section 404). 502.14 Motor vehicle operation. In areas where motor vehi- cles 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 vehi- cles being operated or repaired are electrically pow- ered. 2. 'fhis section shall not apply to one- and two-fanuly 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. ❖ In repair garages, parking garages, warehouses, vocational shops and similar locations where internal combustion engines are operated, engine exhaust contamination can accumulate. To prevent the accu- mulation of harmful contaminants, these spaces must have mechanical ventilation as prescribed in Section 403. For example, Table 403.3 specifies an exhaust rate of 0.75 cfm/ft2 [0.00381 m3/(s • m2)] for repair garages. This section requires mechanical ventilation to be provided and Note b of Table 403.3 specifically requires mechanical exhaust where it is indicated for an occupancy in Table 403.3. The intent is to contain the contaminants in that occupancy, thus preventing the contaminants from migrating or being transferred to other occupancies. It should be noted that Note b does not permit the recirculation of the minimum required amount of venti- lation air to any other occupancies (see commentary, Section 403.2.1). For example, where an air-handling unit serves both a repair garage and the sales floor of a car dealership, recirculation of air from the repair � garage to the sales floor is not permitted. Note that if the air-handling unit served only the repair garage, then air could be recirculated through the unit and back to the repair garage for the purpose of condition- ing the space. In addition to mechanical ventilation being required for the space, a source capture system is required where stationary motor vehicles operate. A saurce capture system is defined as a mechanical system designed to capture the contaminats at their source and discharge them to the outdoor atmosphere. The source capture system must connect directly to the vehicle's exhaust system. A number of repair garages have large overhead doors to permit the movement of vehicles in and out of the service area. Because of the size of the over- head doors, these spaces usually meet the require- ments for natural ventilation in Section 402.2 of th code. Note t at this section, in conjunction with Sec- tion 401.6 of the code and Section 1203.4.2 of the IBC, requires installation of a mechanical exhaust system in spaces where motor vehicles operate. herefore, a repair garage must be mechanically ven- tilated; providing natural ventilation is not an accept- able option. Note that Exception 3 would not require mechanical ventilation where the engines are oper- ated inside the building only for the duration neces- sary to move the vehicles in and out (see commentary for Exceptian 3). The requirement for repair garages to have mechanical exhaust also requires an approximately equal amount of makeup air to be provided (see com- mentary, Section 501.3). It is not uncommon for repair garages to have exhaust fans in the e�erior wall of a garage. When the outdoor temperature permits, this exhaust is usually intended to provide ventilation by exhausting the air in the garage while the outdoor makeup air enters through the open overhead doors or motorized wall louvers that simultaneousfy operate with the exhaust fans. It should be noted that while this system might be sized to provide the required 0.75 cfm/ft2 [0.00381 m3/(s • m2)] of exhaust when the outdoor temperature is moderate, this system may see little use during colder temperatures, especially in more northern climates. For this system to be accept- able, the method to heat the incoming makeup air must be indicated (i.e., the heating system must have sufficient capacity to perform such a task). Motor vehicle operation would also include forklifts, with an internal combustion engine, in a warehause. Note that the code does not have any specific require- ments that address a method to deal with the exhaust from forklifts operating in a warehouse. Lacking any specific requirements, the mechanical exhaust sys- tem required for a public parking garage is the closest occupancy in Table 403.3. A public parking garage requires 0.75 cfm/ft2 [0.00381 m3/(s • m2)] of floor area of outdoor and exhaust air, which would be a substan- tial amount of air in a large warehouse. In lieu of pro- viding 0.75 cfm/ft2 [0.00381 m3/(s • m2)] of outdoor and 2012 INTERNATIONAL MECHANICAL CODE� COMMENTARY 5-24