Two critical code changes have been recently implemented that affect control damper requirements and outside air management.  The first (Section 403 of the International Mechanical Code) requires that constant ventilation requirements be maintained for all HVAC systems – including VAV systems.  The second (International Energy Conservation Code, IECC) requires that outside air dampers have a leakage rating of 3 cfm/ft² or less – thus maintaining energy savings in a zone during unoccupied hours.

Ruskin has the solution for both of these needs!!

Ruskin’s IAQ50 and AMS50 were designed specifically to maintain constant ventilation rates on VAV systems.  In thousands of installations around the world, Ruskin has successfully helped designers meet the challenge of ventilation on VAV systems.  The IAQ50 and AMS50 damper system modulates outside air dampers in response to pressure changes driven by the VAV supply fan.  As the supply fan increases flow, the IAQ50 and AMS50 close to maintain design ventilation criteria.  Conversely, as the supply fan modulates to lower airflows, the Ruskin control system opens the outside air damper to maintain exacting control.  The IAQ50 has the added benefit of factory testing and controller calibration. 

As far as meeting the IECC, Ruskin’s IAQ50 and AMS50 both meet the tight leakage shutoff requirements of 3 cfm/ft².  If HVAC system designers do not require the IAQ50 or AMS50 control logic, Ruskin offers many control dampers that meet the IBC leakage requirements.  Ruskin models CD60, CD50, CDTI50, CD40, CD40X2, and CD403 dampers all meet the tight requirements of 3 cfm/ft² and less. 

 ACTION:

• Read the Engineering Report entitled ‘Code Requirements for the IAQ50, AMS50, CD60. CD50, CDTI50, and CD40 Type Dampers’  by Tom Edwards, President of Ruskin.  Tom is also the current President of the Air Moving and Control Association (AMCA). 
• Be certain to specify control logic that maintains design ventilation rates on all VAV jobs. Also, be certain to follow the code for 3 cfm/ft² and less outside air damper leakage on all outside air dampers!
• Call your Ruskin Representative if you need any assistance on selecting and specifying the right Ruskin dampers!