General Commercial Install Tips and Procedures


INTRO




Counter-flow heat exchangers are theoretically capable of achieving 100% Effectiveness





Parallel Flow heat exchangers: 50% (Max)






Cross-flow heat exchangers: 50-70% (Max)







ROOF TOP




-ERM Mounts should run perpendicular to the length of the Heat Exchanger core

-Mounts should be placed as shown in the diagram

-Mounting equipment should be reinforced by the interior ceiling joists below

-ERM should be securely attached to the mounting system. Design must meet local Wind Load requirements (Unistrut recommended)






HANGING INSTALL






-Hang from ceiling joists
-Use span tables to check point loads
-Properly size threaded rod for weight
-Use vibration dampers at connections
-Supply OA to local Return or Directly to Space
-Exhaust directly outdoors






- Employed good hanging techniques - Insulated OA ductwork for Dew Point prevention - Perfect duct transitions and connections to fans and ERM - Right sized louvers and goosenecks for Exhaust and Intake Points - Area of Improvement: Straighter Duct runs from fan to ERM













FAN INSTALL





TEXT




Intake and Exhaust Louvers



-Bird screens
-Filter box (if required)
-Proper filtration efficiency (MERV, HEPA)
-Sized for 400 fpm (free velocity) to prevent water intrusion
-Louvers that are not within walls should be supported and designed for snow and wind loads








ELECTRICAL


All electrical elements should be installed as per manufacturers’ instructions (fans, controls, pumps, etc.)

All electrical elements should be installed by a professional electrician








GENERAL REQUIREMENTS



Designing for Air Balancing: The ventilation air distribution system shall be provided with a means to adjust the system to achieve at least the minimum ventilation airflow as required by ASHRAE Standard 62.1-2007 or local code, whichever is more stringent.

Exhaust Duct Location: Exhaust ducts that convey potentially harmful contaminant shall be negatively pressurized relative to spaces through which they pass, so that exhaust air cannot leak into occupied space; supply, return, or outdoor air ducts; or plenums.
 
Ventilation System Controls: Mechanical ventilation systems shall include controls, manual or automatic, that enable the fan system to operate whenever the spaces served are occupied. The system shall be designed to maintain the minimum outdoor airflow as required by Section 6 of ASHRAE Standard 62.1 – 2007 or local code, whichever is more stringent.

Airstream Surfaces: All airstream surfaces in equipment and duct in the heating, ventilating, and air-conditioning system shall be designed and constructed to be resistant to erosion.

Outdoor Air Intakes: Ventilation system outdoor air intakes shall be designed in accordance with the following:

Location: Outdoor Air intakes, including doors and windows, shall be located such that the shortest distance from the intake to any specific potential outdoor contaminant source shall be equal to or greater than the separation distance listed in Table 5-1, Air Intake Minimum Separation Distance, of ASHRAE Standard 62.1 – 2007.
 

Rain Entrainment: Outdoor air intakes that are part of the mechanical ventilation system shall be designed to manage rain entrainment. Outdoor air intakes should be designed for 400 fpm for flows of 7,000 cfm or greater and 300 fpm for flows below that range. FPM shall refer to the face velocity of outdoor air into the intake or louver in feet per minute.

Rain Intrusion: Air-handling and distribution equipment mounted outdoors shall be designed to prevent rain intrusion into the airstream when tested at design airflow and with no airflow.

Snow Entrainment: Where climate dictates, outdoor air intakes that are part of the mechanical ventilation system shall be designed to manage melted snow blown or drawn into the system.

Bird Screens: All outdoor air intakes shall include a screening device designed to prevent penetration by a 0.5 in. diameter probe. The screening device material shall be corrosion resistance. The screening device shall be located, or other measures shall be taken to prevent bird nesting within the outdoor air intake.

Maintenance: Suitable access door should be provided to filters and equipment to permit cleaning.

Drainage: Outdoor air ductwork or plenums shall pitch to drains designed in accordance with the requirements of Section 5.11 of ASHRAE Standard 62.1 – 2007.