7.1 Ventilation design guide

Mechanical designs should be economical, maintainable, and energy efficient, with full consideration given to the functional requirements and planned life of the facility. Mechanical design should also consider life-cycle operability, maintenance, and repair of the facility and real property-installed equipment, components, and systems. Ease of access to components and systems in accordance with industry standards and safe work­ing practices is a design requirement.

The best way to prevent IAQ problems is to have appropriate and effective engineer­ing controls in place to maintain the indoor air quality. The following is an example of design criteria guidance that should be discussed throughout the design phase. Various boxes throughout the chapter illustrate the real-world concerns from which this guidance was derived.

7.2 Example design conditions guidance

The following conditions should be used and will need to be investigated in designing the mechanical systems:

• Site Elevation: Equipment design elevation is {insert} feet (meters) above

sea level. Appropriate corrections should be made when calculating the capacity of all mechanical equipment installed at this elevation.

• Latitude: {insert} Deg N

• Heating Degree Days: {insert} annual

• Cooling Degree Days: {insert} annual

7.2.1 Outside Design Conditions

Winter:

{insert} °F (°C) for outside makeup air and infiltration loads

{insert} °F (°C) for air transmission loads

Summer:

{insert} °F (°C) dry bulb

{insert} °F (°C) maximum condensation wet bulb

7.2.2 Inside Design Conditions

Winter:

{insert} °F (°C) for occupied administration areas

{insert} °F (°C) for mechanical/electrical areas

Summer:

{insert} °F (°C) for occupied administration areas

{insert} °F (°C) for mechanical/electrical areas

7.3 Mechanical room layout requirements

Mechanical equipment room layout should have ample floor space to accommodate routine maintenance of equipment and adequate headroom to accommodate specified equipment. Ample space should be provided around equipment to allow unobstructed access for servicing and routine maintenance. This space allotment should include ample areas for service and/or replacement of coils, tubes, motors, and other equipment.

Provisions for installation and future replacement of equipment should be coordinated with the architectural design. The arrangement and selection of mechanical equipment should not interfere with complete removal of the largest piece of equipment without dis­mantling adjacent systems or structures. Doors should be located to facilitate such service.

7.4 Electrical equipment/panel coordination

Arrangement of all mechanical equipment and piping should be coordinated with electrical work to provide dedicated space for panels, conduit, and switches. Clearance required by the NEC above and in front of electrical panels and devices should be pro­vided. Mechanical equipment (pipes, ducts, etc.) should not be installed within space that is dedicated to electrical switchboards and panel boards (see NFPA 70 Article 384-4). When

electrical equipment is located in a mechanical equipment room, dedicated electrical space including a proper safety envelope must be available.