NOTE This standard covers complete, factory-assembled window units procured from a single manufacturer as a finished assembly. (1.1)

NOTE A window unit under this standard arrives with its frame, sash, glazing, weatherstripping, and operating hardware already assembled and rated as one product. The contractor sets and flashes it into a prepared rough opening; the contractor does not field-fabricate the frame or grid. This is the distinction that separates a window from a storefront or curtain wall, where the framing is assembled stick by stick in the opening and the glazing is infilled on site. (1.2)

NOTE Boundaries with adjacent fenestration systems are drawn so that each assembly type is specified once, under the standard that governs its method of assembly. (1.5)

NOTE The dividing line is how the assembly is built and where it sits relative to the weather line. Field-assembled aluminum grid with infill glazing is storefront or curtain wall. Glazing that sits above the weather line on a slope is a skylight. Glass and interlayers specified on their own, apart from any unit, are glazing materials. Each is named below so the reader retargets rather than duplicating requirements here. (1.6)

NOTE The following adjacent systems are excluded from this standard and are each specified once under the standard that governs their method of assembly: (1.7)

NOTE The AAMA-numbered standards below are maintained by the Fenestration and Glazing Industry Alliance (FGIA), which absorbed AAMA and IGMA in 2020; the AAMA designations remain current under the FGIA umbrella. (2.3)

NOTE Energy code compliance shall be demonstrated by NFRC-labeled ratings; generic or uncertified manufacturer performance claims are not acceptable to the energy inspector. (4.4)

NOTE Energy inspectors verify fenestration against the NFRC label on the unit. A manufacturer datasheet that states a U-factor without an NFRC certification number will be rejected, forcing a substitution or a re-rate late in construction. Specify NFRC-labeled product and require the label to remain on the unit until inspection. (4.5)

NOTE Approved mock-ups may remain as part of the permanent work if undamaged and indistinguishable from production units. (4.7)

NOTE NAFS sorts window units into four performance classes that set the minimum structural, air, and water test requirements; the class is chosen from the building's exposure and occupancy, not from price. (5.1)

NOTE The four NAFS product classes are Residential (R), Light Commercial (LC), Architectural (AW), and Commercial (CW). R and LC are tested to higher air and water limits relative to their grade and suit houses and low-rise multifamily. AW is the most demanding class, intended for high-rise and heavy commercial exposure, with the tightest air leakage and the most stringent water and life-cycle testing. CW sits between LC and AW for mid-rise commercial. The class is a floor; the Performance Grade then fixes the design pressure within that class. (5.2)

NOTE The Performance Grade (PG) sets the design pressure the unit must resist and shall be derived from a project-specific wind analysis, not assumed. (5.4)

NOTE Performance Grade is the design pressure in pounds per square foot (psf) that the unit is tested to resist per ASTM E330, with the water test conducted at 15% of that pressure as a minimum. PG 15 is the residential default; PG 30 is a common light-commercial value; PG 40 and above suit architectural and coastal exposures. The grade must come from an ASCE 7 wind analysis that gives design pressures zone by zone across the elevation, because corner and parapet zones see higher pressures than the field of the wall. (5.5)

NOTE Specifying a residential-default Performance Grade on a commercial or high-exposure building leaves the units undersized for the actual wind load and is a frequent source of structural and water failures. (5.7)

NOTE Frame material is the first selection and governs thermal performance, maximum unit size, maintenance, and cost; no single material is correct for every application. (6.1)

NOTE Aluminum frames are strong and dimensionally stable but conduct heat, so commercial aluminum windows must be thermally broken to meet energy code. Vinyl (PVC) is inexpensive and thermally efficient but creeps under thermal cycling and is limited in size and grade. Wood is warm and traditional but needs maintenance unless clad with aluminum or vinyl on the exterior. Fiberglass and composite frames offer low thermal conductivity and good dimensional stability across temperature swings, and suit cold climates and large openings. (6.2)

NOTE Vinyl-framed units shall not be specified above approximately 1.5 m (5 ft) in width or above Performance Grade 40 without the manufacturer's documented test evidence at the required size and grade. (6.4)

NOTE Vinyl creeps and bows under thermal cycling, and large vinyl frames lose stiffness as they heat. Pushing vinyl beyond roughly 5 ft wide or beyond PG 40 invites sash binding, air and water infiltration, and warranty disputes. Large or high-grade commercial openings should use aluminum, fiberglass, or composite frames. (6.5)

NOTE Operating type is selected from the ventilation need, the reach to the operator, the elevation pattern, and egress requirements. (6.6)

NOTE Fixed (picture) units do not ventilate and give the largest glass area. Double-hung and single-hung sashes slide vertically and wash easily on the interior. Casements crank outward and seal tightly against their frame, giving good air performance, while awnings hinge at the top to shed rain while open. Hoppers hinge at the bottom and suit below-grade and high-wall locations. Sliders glide horizontally for wide low openings. Projected and tilt-turn units serve commercial elevations and dual cleaning/ventilation modes. The choice drives hardware, egress capability, and rough opening size. (6.7)

NOTE The frame depth shall be coordinated with the wall section so that the frame, nailing flange or pocket, and interior/exterior trim resolve without modification. (6.9)

NOTE Thermally broken commercial aluminum frames are commonly 83-114 mm (3.25-4.5 in) deep. The frame depth must match the wall assembly thickness, the WRB plane, and the trim conditions shown in the wall section, or the units will not align with the cladding and interior finish. (6.10)

NOTE Whole-window thermal performance is rated by NFRC procedures and must meet the prescriptive maximums for the project's climate zone or the values set by the energy model. (7.1)

NOTE The whole-window U-factor (NFRC 100) measures heat flow through the frame, edge, and center of glass together; a center-of-glass figure alone overstates performance. Solar Heat Gain Coefficient (NFRC 200) controls solar gain and is tuned by the low-e coating. Visible Transmittance (NFRC 200) governs daylight. Energy code compliance is shown either against the prescriptive U-factor and SHGC table for the climate zone (IECC for residential and low-rise, ASHRAE 90.1 for commercial) or through a whole-building energy model trade-off. (7.2)

NOTE The air leakage rate shall be NFRC 400 / ASTM E283 rated and shall not exceed the scheduled limit at the test pressure. (7.6)

NOTE The NAFS standard limit for R and LC classes is 0.30 cfm/ft² at 1.57 psf; AW and CW units, and energy-sensitive projects, are commonly specified at 0.10 cfm/ft². Air leakage is the difference between a window that meets a blower-door target and one that does not, so it should be specified explicitly rather than left to the class minimum. (7.7)

NOTE Condensation resistance shall be specified for cold-climate and high-humidity-interior projects, because a low U-factor alone does not guarantee a warm interior glass and frame surface. (7.8)

NOTE The Condensation Resistance rating (NFRC 500, range 1-100, higher is better) predicts how well the warmest interior surfaces resist condensation. A U-factor-only specification can still allow cold frame edges that sweat or frost in Climate Zone 5 and above, or in natatoriums, pools, and hospitals where interior humidity is high. Specify a minimum CR for those conditions. (7.9)

NOTE Glazing makeup is selected with the thermal targets, because the insulating glass unit and its low-e coating do most of the work of meeting U-factor and SHGC. (8.1)

NOTE A single insulating glass unit (IGU) with a low-e coating and an argon fill is the residential and light-commercial baseline. Triple glazing adds a third lite and a second cavity for Climate Zones 6 through 8 and for acoustic or comfort-critical interiors. The low-e coating type and its surface position tune SHGC against VT, and the warm-edge spacer reduces edge heat loss and condensation. Detailed glass and interlayer specification is the province of Glazing; here the unit-level makeup is selected. (8.2)

NOTE For residential sleeping rooms, IRC R310 requires a net clear opening area of at least 5.7 ft² (4.5 ft² at grade-floor openings), a minimum clear height of 24 in, a minimum clear width of 20 in, and a sill no higher than 44 in above the finished floor. These are clear-of-hardware dimensions after the sash is opened, so the rough unit size must be selected to satisfy them. Omitting egress from the plans forces a sash change order late in construction. (9.3)

NOTE Fall-prevention or sash-limiting devices shall be provided on operable windows where required by code for the sill height and floor level above grade. (9.6)

NOTE Operable windows with low sills on upper floors can present a fall hazard, and many codes require window opening control devices or limited initial openings on floors above the ground level. The limiting device must still allow the window to reach its full egress opening when released, so the hardware must be selected to satisfy both the fall-prevention limit and the egress opening. (9.7)

NOTE In hurricane-prone and high-wind regions, impact resistance shall be specified by citing the ASTM E1996 product type and missile level, or the governing local code, so that manufacturers submit equivalent products. (10.1)

NOTE "Impact-rated" with no further definition lets each manufacturer submit a product to whatever level it chooses. ASTM E1996 defines missile levels (large-missile levels such as D and E, and small-missile levels) tied to wind speed and the height of the glazing above grade. Hurricane jurisdictions add their own approval and labeling rules. The Florida Building Code and the Texas Department of Insurance impose product-approval and labeling requirements beyond base IBC that affect which products may be installed, so the design pressure, the missile level, and the local approval basis must all be stated. (10.2)

NOTE The aluminum frame finish shall be specified by AAMA finish class and shall match the finish class of any storefront or curtain wall on the same elevation. (11.1)

NOTE Aluminum frame finishes are graded by durability. AAMA 2603 is a standard organic coating; AAMA 2604 is a high-performance coating with roughly 50% PVDF resin; AAMA 2605 is a superior coating with at least 70% PVDF resin and a long chalk-and-fade warranty, and is the default for exposed commercial work. Anodized finishes follow AAMA 611. The critical coordination rule is that all aluminum on one elevation must share a finish class, because a lower-durability coating fades and chalks at a different rate and the color will visibly diverge within a few years. (11.2)

NOTE Sill drainage (weep) paths shall be provided and shall remain clear so that water reaching the sill track drains to the exterior. (12.4)

NOTE Operable units collect water in the sill track. Concealed weep slots must drain that water out the face of the unit; if they are blocked by sealant during installation, water backs up and enters the wall. The drainage path is part of the unit and must be protected during glazing and setting. (12.5)

NOTE Window units shall be installed in accordance with ASTM E2112 and the manufacturer's written instructions, integrated with the wall's water-resistive barrier so that water is directed to the exterior at every interface. (13.1)

NOTE ASTM E2112 governs the order of operations that makes a window watertight: the sill pan goes in first and drains outward, the unit is set and shimmed, jamb flashing laps over the sill pan, and head flashing laps over the jamb flashing and behind the WRB above. Every overlap sheds water downward and outward. Get the sequence wrong and the window leaks regardless of how well the unit itself performs. (13.2)

NOTE The window-to-wall interface shall be sealed and insulated so that the rough opening framing and subsill do not become a thermal bridge that defeats the thermally broken frame. (13.6)

NOTE A thermally broken frame loses much of its value if the surrounding rough opening is uninsulated. The shim space must be insulated (low-expansion foam or mineral wool, not a rigid pack that distorts the frame), and the subsill should include a thermal break. The interior air seal and exterior weather seal are separate planes and both must be continuous. (13.7)

NOTE The rough opening shall be sized to the unit dimension plus the manufacturer's shim allowance, and the rough opening for each window type shall be confirmed on the drawings. (13.9)

NOTE Rough opening size varies by operating type and manufacturer. A common allowance is the unit size plus about 1/2 in total each direction, giving roughly 1/4 in of shim space per side. A single generic rough-opening note across a project with mixed window types generates RFIs and field rework, so each type's rough opening must be scheduled. (13.10)

NOTE Factory-glazed and field-glazed units shall not be intermixed within a single submittal without a clear designation of which units ship glazed and which are glazed on site. (13.12)

NOTE Large fixed lites are sometimes shipped with the glass separate and glazed in the opening to manage weight and breakage. A factory-glazed unit and a field-glazed unit warranty and behave differently, so the submittal must state which units are which to avoid schedule and warranty confusion. (13.13)

NOTE Protective films and labels shall remain in place until directed for removal, and labels required for energy inspection shall not be removed before inspection. (14.3)

NOTE The exterior frame finish shall be warranted against chalk, fade, and adhesion loss for the period associated with its AAMA finish class. (15.3)

NOTE AAMA 2605 finishes carry a long exterior warranty, commonly on the order of ten to twenty years against fade and chalk, while AAMA 2604 and 2603 carry shorter periods. The finish warranty period should match the finish class specified and the exposure of the elevation. (15.4)