6.6203.2 Dehumidifying Ventilator Serving Multiple Dwelling Units (All Building Types)

Topic:

Whole Building Ventilation

Subtopic:

Dehumidifiers

Desired Outcome:

Humidity controlled to achieve optimum indoor air quality ( IAQ IAQ Indoor air quality )

Note:

The authority having jurisdiction may require that a licensed professional perform certain tasks outlined in this detail.

For supporting material, see Referenced Standards.

Multifamily Homes

Title	Specification(s)	Objective(s)
6.6203.2a Equipment specification	Specifications will be field verified as appropriate to site conditions by installer Equipment will be ENERGY STAR® qualified (where applicable) Settings will be maintained through power failure (auto restart) Dehumidification ventilator will be a ducted unit Dehumidification ventilator will be able to provide outside air	Efficiently remove humidity Ensure ease of operation Provide ventilation with outside air Ensure appropriate equipment is specified Ensure design and installation are feasible
6.6203.2b Sizing	System with enough capacity to handle humidity from outside air ventilation and internal gains will be selected Humidity levels inside the space will be maintained at less than 60% Note: As outdoor temperature drops, indoor humidity will need to be low enough to prevent condensation in building enclosure ASHRAE ASHRAE American Society of Heating, Refrigerating and Air-Conditioning Engineers, www.ashrae.org 62.2 and local code requirements should be followed for identifying design airflow rates within apartment dwelling units. All other areas will follow local code requirements and/or ASHRAE ASHRAE American Society of Heating, Refrigerating and Air-Conditioning Engineers, www.ashrae.org 62.1-2010 requirements Air flows will be measured in accordance with ANSI ANSI American National Standards Institute, www.ansi.org / ACCA ACCA Air Conditioning Contractors of America, www.acca.org Standard 5 or ANSI ANSI American National Standards Institute, www.ansi.org / ASHRAE ASHRAE American Society of Heating, Refrigerating and Air-Conditioning Engineers, www.ashrae.org Standard 111 and adjusted to meet design requirements	Efficiently remove humidity Provide sufficient outdoor air to desired locations Avoid moisture problems associated with over ventilation in a hot and humid climate
6.6203.2c Access	Equipment will be located in an area with access to heating, ventilation, and air conditioning supply trunk line or plenum, outside air Fans, service switch Service switch An electrical switch that controls the complete flow of electricity to a mechanical device , filters, drain, and drain pan will be accessible for maintenance or replacement	Easily maintain equipment Maintain designed air flows and system performance Ensure occupant health and safety
6.6203.2d Installation	Installation will be in accordance with manufacturer specifications and local codes Dehumidifying ventilator will be mounted securely in accordance with manufacturer specifications and local code Requirements (in terms of seismic restraints) Dehumidifying ventilator will be oriented so the equivalent length of the duct run is as short as possible Dehumidifying ventilator will be isolated from the building framing unless specifically designed to be directly attached	Maintain manufacturer warranty and proper installation Ensure short duct runs achieve optimum air flows Ensure dehumidifying ventilator is mounted securely Ensure dehumidifying ventilator housing or building framing does not shake, rattle, or hum when operating Minimize noise
6.6203.2e Controls	Operation of the dehumidifier will be based upon humidity/temperature in the return air, or provide supply air at a specified temperature and humidity	Ensure system operation controls the humidity
6.6203.2f Wiring	Wiring will be installed by a licensed contractor Wiring will be installed in accordance with original equipment manufacturer specifications, and local and national electrical and mechanical codes Refer to NFPA NFPA National Fire Protection Association, www.nfpa.org 70: National Electrical Code for installation requirements	Prevent an electrical hazard
6.6203.2g Condensate drain	Condensation shall be drained to a location approved by the local jurisdiction	Prevent moisture problems
6.6203.2h New connecting ductwork	All exposed ductwork outside of the building will be insulated to a minimum R-12, protected from weather exposure and sealed at all penetrations into building shell All ductwork outside of conditioned space will be insulated to a minimum of R-8	Ensure durability and energy efficiency of ductwork
6.6203.2i Distribution systems	Note: Dehumidifying ventilator provides the outdoor air supply fan The rest of the ventilation system will be installed in accordance with SWS 6.6104.1 Outdoor Supply Air Handling Unit Serving Multiple Dwelling Units or Corridors (All Three Building Types)	Achieve the desired air flows to and from the desired locations Preserve integrity of the duct system and building envelope Envelope The separation between the interior and exterior environments of a building that includes a combination of air and thermal barrier
6.6203.2j Verification	Verification of the dehumidification unit and controls will be performed and documented	Ensure the performance of the ventilation system Ensure occupant health and safety
6.6203.2k Fire dampers	Fire dampers must be accessible for inspection and/or testing by the local authorities; if fire dampers are not accessible from a grill or register, an access door in the ductwork is required Sealing activities will not interfere with the operation of fire dampers, balancing dampers, or backdraft dampers Type B fire dampers will be used as required by fire code	Ensure access to fire dampers for safe operation Minimize static pressure Maximize air flow
6.6203.2l Property manager education	Property manager will be educated on purpose of system, and how and when to change filter and clean drain pan, if applicable, in accordance with manufacturer specifications	Ensure occupant health and safety Preserve integrity of system