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The residential inspection checklist for topout/frame (mechanical) includes:

  • Attic HVAC: Equipment installed per manufacturer’s specifications and listing***Please note: The additional mechanical (HVAC equipment) dead load must be considered in the rafter design and/or engineered roof truss design.
  • Attic HVAC: Minimum 22” x 30” access opening for equipment servicing, section M1305.1.3, I.R.C. 
  • Attic HVAC: Attic passageway (with continuous solid flooring) for equipment servicing and removal, maximum 20 foot length, minimum 22 inch width, minimum 30 inch head clearance, with a minimum 30” x30” (floored) service space at all equipment access locations, section M1305.1.3, I.R.C. 
  • Attic HVAC: Drain pan, along with primary and secondary condensate drain lines. Horizontal drain lines slope at a min. 1/8 inch per foot without any sags.  Secondary condensate drain line must terminate at a conspicuous point to alert occupants, section M1411.3.1, I.R.C. 
  • “B” vent (draft-hood-equipped appliance): Install per manufacturer’s specifications and listing, with min. 1 inch clearance to combustibles (unless otherwise listed), including gypsum wallboard and added insulation (insulation shield to extend a min. 2 inches above top of insulation).
  • “B” vent: Extends in general vertical direction with max. 45 degree offsets (note: one 60 degree offset allowed). Horizontal vent distance (including horizontal vent connector) not to exceed 75% of vertical height of vent, unless otherwise listed, section G2427.6.8.2 I.R.C. 
  • “B” vent: Vent termination, minimum 8 feet from any vertical wall or similar obstruction and a height above highest point of roof penetration (12 inches for roof slope up to 6/12) per Figure G2427.6.3 I.R.C. 
  • “B” vent: Extend thru roof flashing, roof jack or roof thimble and terminate with a listed cap, section G2427.6.5, I.R.C. 
  • Combustion air: In a garage, vents located within 12 inches of ceiling and 12 inches of floor, sized per section G2407.6.1, I.R.C. 
  • Combustion air: Within insulated building envelope, combustion air venting must be in compliance with section G2407.5.3, I.R.C. 
  • Metal ductwork fabrication and installation, section M1601, I.R.C. 
  • Metal ducts shall be supported (min. ½ inch wide / 18-gage straps or 12-gage galv. wire) at intervals not exceeding 10 feet oc, section M1601.4.3, I.R.C. 
  • Nonmetallic ducts to be supported per manufacturer’s specifications and listing, with no kinks and no sags, section M1601.2, I.R.C. 
  • Duct joints and seams to be made substantially airtight by means of tapes and mastics meeting UL 181 standard, section M1601.4.1, I.R.C. 
  • Duct connections to flanges of air distribution fittings / equipment to be mechanically fastened. Crimp joint for round metal ducts: minimum contact lap of 1 inch and mininum three (3) sheet-metal screws, section M1601.4.1, I.R.C. 
  • Dryer vent: Maximum duct length: 35 feet minus 2.5 feet for each (4 inch radius) 45-degree elbow fitting and minus 5 feet for each (4 inch radius) 90-degree elbow fitting, section M1502.4.4.1, I.R.C. 
  • Dryer vent: Ductwork construction: minimum 0.016-inch-thick rigid metal, with smooth interior surfaces with joints running in the direction of air flow ***Please note: Sheet-metal screws or other fasteners are allowed to extend maximum 1/8 inch into the inside of the duct, section M1502.4.1 and M1502.4.2, I.R.C. 
***Please note:  Protective shield plates shall extend a minimum of 2 inches above sole plates and below top plates, section M1502.5, I.R.C.
  • Ridge vent, soffit vent, gable vent, "O-hagen" cloaked tile vent openings sized in compliance with section R806.2, I.R.C. 

Contact Information 

City of Litchfield Park
Building Safety Department
214 West Wigwam Boulevard
Litchfield Park, Arizona  85340

Ph: 623-935-1066
Fx: 623-535-9754

Updated 4/22/16