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(continued)
buildings
Wood and wood products:
Hardboard PS 58, 59,
$ 60-1973
Hardwood and decorative plywood USDC PS 51-71
Structural design guide for hardwood plywood HPMA-SG-71
Timber, structural glued laminated-inspection AITC-200-1973
Timber, structural glued laminated USDS PS 56-73
Construction and industrial plywood PS 1-74
Plywood residential construction guide APA-1975

Design specifications for plywood-lumber components APA-1974
Fabrication specifications of plywood-lumber components APA-1975
Stress grade lumber and its fastenings-national design (N) FPA-1973
specifications for (and supplement)
Structural design data-wood (N) FPA-1970
Span tables for joists and rafters (PS 20-70) (N) FPA-1973
Working stresses for joists and rafters (N) FPA-1974
Timber construction standards AITC-100-1972
Design specifications for light metal plate connected wood TPI-74
trusses
Span tables for light metal plate connected wooden trusses TPI-1972
Particleboard for mobile home decking NPA 1-73
Mat-formed wood particleboard CS 236-66
All plywood beams for mobile homes APA 124-74
Wood flush doors (interior, exterior) NWMA I.S.1-74
Wood window units ANSI
A200.1-74
(NWMA
I.S.2-73)
Water repellent preservative treating for millwork NWMA I.S.4-70
Wood patio doors NWMA I.S.3-70

Other: Gypsum wallboard ASTM C36
Fasteners:
Nails, brads, staples and spikes, wire, cut & wrought 5F.S. FF-N-1
5b
Pneumatic and mechanically driven building construction I-SAN
fasteners TA-19-73
Windows and glazing: Transparent safety glazing material used in ANSI A58.1-97
buildings
Unclassified: Building code requirements for minimum design ANSI
loads in buildings and other structures A58.1-197


(c) Wood products shall be identified as complying with the appropriate standards.
280.305. Structural Design Requirements.
(a) Each mobile home shall be designed and constructed as a completely integrated structure capable of sustaining the design load requirements of this standard and shall be capable of transmitting these loads to stabilizing devices without exceeding the allowable loads stresses or deflections. Roof framing shall be securely fastened to wall framing, walls to floor structure, and floor structure to chassis to secure and maintain continuity between the floor and chassis, so as to resist wind overturning and sliding as imposed by design loads in this Part. Uncompressed finished flooring greater than 1/8 inch in thickness, shall not extend beneath load bearing walls which are fastened to the floor structure.
(b) Design Loads.
(1) Design dead loads. Design dead loads shall be the actual dead load supported by the structural assembly under consideration.
(2) Design live loads. The design live loads and wind and snow loads shall be as specified in this Section and shall be considered to be uniformly distributed. The roof live load or snow load shall not be considered as acting simultaneously with the wind load and roof live or snow load and floor live loads shall not be considered as resisting the overturning movement due to wind.
(3) When engineering calculations are performed, allowable unit stresses may be increased as provided in the documents referenced in 280.304 except as shown otherwise in 280.306(a).
(c) Wind, snow and Roof Loads.
(1) Standard Wind (Zone I). When a mobile home is not designated as 'Hurricane-Resistive,' the mobile home and each wind resisting part and portion thereof shall be designed for horizontal wind loads not less than 15 psf and a net uplift load of not less than 9 psf.
(2) Hurrican Resistive (Zone II). (i) When a mobile home is designated as 'Hurricane Resistive,' the home and each wind resisting part and portion thereof shall be designed for horizontal wind loads not less than 25 psf and a net uplift not less than 15 psf. (ii) For exposures in coastal and other areas where wind records indicate significant differences, 125 mph or greater, from the wind loads stated above, the Department may establish more stringent requirements for homes known to be destined for such areas.
(3) Roof Loads.
(i) Flat, curved and pitched roofs shall be designed to resist the following live loads, applied downward on the horizontal projection as appropriate, for the design zone marked on the mobile home:

Pounds per square foot
North Zone 40
Middle Zone 30
South Zone 20


(ii) For exposures in areas (mountainous or other) where snow or wind records or experience indicate significant differences from the loads stated above, the Department may establish more stringent requirements for homes know to be destined for such areas. For snow load, such requirements are to be based on a roof snow load of 0.6 of the ground snow load of areas exposed to wind and roof snow load of 0.8 of the ground snow load for sheltered areas.
(iii) Eaves and cornices shall be designed for a net uplift pressure of 2.5 times the design uplift wind pressure cited in 280.305(c)(1) and (2).
(4) The Data Plate posted in the mobile home (See 280.5) shall show for each structural zone(s) of the USA the mobile home has been designed and the actual design external snow and/or wind live loads. The Data plate shall include reproduction of the Load Zone Maps shown in this Section and related information. The Load Maps shall be not less than one-half he size illustrated.
WIND ZONE MAP

STANDARD WIND ZONE I 15 PSF Horizontal 9 PSF Uplift

HURRICANE ZONE II 25 PSF Horizontal 15 PSF Units



Design Load Deflection. When a structural assembly is subjected to total design live loads, the deflection for structural framing members shall not exceed the following:

Floor L/240
Roof and ceiling L/180
Headers, beams, and girders (vertical load) L/180
Walls and partitions L/180


Where L equals the clear span between supports or two times the length of a cantilever.
(e) Fastening of Structural Systems. Roof framing shall be securely fastened to wall framing, walls to floor structure, and floor structure to chassis to secure and maintain continuity between the floor and chassis, so as to resist wind overturning and sliding as imposed by design loads in this Part.
(f) Walls. The walls shall be sufficient strength to withstand the load requirements as defined in 280.305(c) of this part, without exceeding the deflections as specified in 280.305(d). The connections between the bearing walls, floor, and roof framework members shall be fabricated in such a manner as a manner as to provide support for the material used to enclose the mobile home and to provide for transfer of all lateral and vertical loads to the floor and chassis.
(1) Except where substantiated by engineering analysis or tests, studs shall not be notched or drilled in the middle one-third of their length.
(2) Interior walls and partitions shall be constructed with structural capacity adequate for the intended purpose and shall be capable of resisting a horizontal load of not less than five pounds per square foot. Finish of walls and partitions shall be securely fastened to wall framing.
(g) Floors.
(1) Floor assemblies shall be designed in accordance with accepted engineering practice standards to support a minimum uniform live load of 40 lb/ft<>2 plus the dead load of the materials. In addition (but not simultaneously), floors shall be able to support a 200-pound concentrated load on a one-inch diameter disc at the most critical location with a maximum deflection not to exceed one-eighth inch relative to floor framing. Perimeter wood joists of more than six inches depth shall be stablized against overturning from superimposed loads as follows: at ends by sold blocking not less than two-inch thickness by full depth of joist, or by connecting to a continuous header not less than two-inch thickness and not less than the depth of the joist with connecting devices; at eight-feet maximum intermediate spacing by solid blocking or by wood cross-bridging of not less than one inch by three inches, metal cross-bridging of equal strength, or by other approved methods.
(2) Wood, wood fibre or plywood floors or subfloors in kitchens, bathrooms (including toilet compartments), laundry rooms, water heater compartments, and any other areas subject to excessive moisture shall be moisture resistent or shall be made moisture resistent by sealing or by an overlay of nonabsorbent material applied with water-resistent adhesive. Carpets and/or carpet pads shall not be installed in concealed spaces subject to excessive moisture such as plumbing fixture spaces.
(3) Except where substantiated by engineering analysis or tests:
(i) Notches on the ends of joists shall not exceed one-fourth the joist depth.

(ii) Holes bored in joists shall not be within 2 inches of the top or bottom of the joist, and the diameter of any such hole shall not exceed one-third the depth of the joist.
(iii) Notches in the top or bottom of the joists shall not exceed one-sixth the depth and shall not be located in the middle third of the span.
(4) Bottom board material (with or without patches) shall meet or exceed the level of 48 inch-pounds of puncture resistance as tested by the Beach Puncture Test in accordance with ASTMD-781-68. The material shall be suitable for patches and the patch life shall be equivalent to the material life. Patch installation instruction shall be included in the mobile home manufacturer's instructions.
(b) Roofs.
(1) Roofs shall be sufficient strength to withstand the load requirements as defined in 280.305(b) and (c) without exceeding the deflections specified in 280.305(d). The connections between roof framework members and bearing walls shall be fabricated in such a manner to provide for the transfer of design vertical and horizontal loads to the bearing walls and to resist uplift forces.

(2) Roofing membranes shall be of sufficient rigidity to prevent deflection which would permit ponding of water or separation of seams due to wind, snow, ice, erection or transportation forces.
(3) Cutting of roof framework members for passage of electrical, plumbing or mechanical systems shall not be allowed except where substantiated by engineering analysis.
(4) All roof penetrations for electrical, plumbing or mechanical systems shall be properly flashed and sealed. In addition, where a metal roof membrane is penetrated, a wood backer shall be installed. The backer plate shall be not less than 5/16 inch plywood, with exterior glues, secured to the roof framing system beneath the metal roof, and shall be of a size to assure that all screws securing the flashing are held by the backer plate.
280.306. Windstorm Protection.
(a) Provisions for support and anchoring systems. Each mobile home shall have provisions for support and anchoring systems, which, when properly designed and installed, will resist overturning and lateral movement (sliding) of the mobile home as imposed by the respective design loads. The design wind loads to be utilized for calculating resistance to overturning and lateral movement shall be the wind loads indicated in 280.305(c) (1) and (2) increased by a factor of safety of 1.5. The basic allowable stresses of materials required to resist overturning and lateral movement shall not be increased in the design and proportioning of these members.
(1) The provisions of this section shall be followed and the support and anchoring systems shall be designed by a Registered Professional Engineer or Architect.
(2) The manufacturer of each mobile home is required to make provision for the support and anchoring systems but is not required to provide the anchoring equipment or stabilizing devices. When the manufacturer's installation instructions provide for the main frame structure to be used as the points for connection of diagonal ties, no specific connecting devices need be provided on the main frame structure.
(b) The manufacturer shall provide printed instructions with each mobile home specifying the location and required capacity of stabilizing devices on which the design is based. The manufacturer shall provide drawings and specifications certified by a registered professional engineer indicating at least one acceptable system of anchorage including the details of required straps or cables, their end connections and all other devices needed to transfer the wind loads from the mobile home to the ground anchors.
(c) The provisions made for anchoring systems shall be based on the following design criteria for mobile homes.
(1) The minimum number of ties required per side shall be as required to resist the design loads stated in 280.305(c)(1) and (2).
(2) Ties shall be as evenly spaced as practicable along the length of the mobile home with not more than 8 feet open-end spacing on each end.
(3) When continuous straps are provided as vertical ties, such ties shall be positioned at rafters and studs. Where a vertical tie and diagonal tie are located at the same place, both ties may be connected to a single ground anchor, provided that the anchor used is capable of carrying both loadings.
(4) Add-on sections of the expandable mobile homes shall have provisions for vertical ties at the exposed ends.

(d) Double-wide mobile homes require only diagonal ties. These shall be placed along the main frame and below the outer side walls.
(e) Protection shall be provided at sharp corners where the anchoring system requires the use of external cables or straps. Protection shall also be provided to minimize damage to roofing or sliding by the cable or strap.
(f) Anchoring equipment shall be capable of resisting an allowable working load equal to or exceeding 3,150 pounds and shall be capable of withstanding a 50 percent overload (4,725 pounds total) without failure of either the anchoring equipment or the attachment point on the mobile home.
(g) Anchoring equipment exposed to weathering shall have a resistance to weather deterioration at least equivalent to that provided by a coating of zinc on steel of not less than 0.30 ounces per square foot of surface coated.
(1) Slit or cut edges of zinc-coated steel strapping do not need to be zinc coated.
(2) Type 1, Finish B, Grade 1 steel strapping, 1 1/4 inches wide and 0.035 inch thick, conforming with Federal Specification QQ-S-781-H, is judged to conform with the provisions of this section and paragraph (f) above.
280.307. Resistance to Elements and Use.
(a) Exterior coverings shall be of moisture and weather resistive materials attached with corrosion resistant fasteners to resist wind, snow and rain. Metal coverings and exposed metal structural members shall be of corrosion resistant materials or shall be protected to resist corrosion. All joints between portions of the exterior covering shall be designed, and assembled to protect against the infiltration of air and water, except for any designed ventilation of wall or roof cavity.
(b) Joints between dissimilar materials and joints between exterior coverings and frames of openings shall be protected with a compatible sealant suitable to resist infiltration of air or water.
(c) Where adjoining materials or assemblies of materials are of such nature that separation can occur due to expansion, contraction, wind loads of other loads induced by erection or transportation, sealants shall be of a type that maintains protection against infiltration or penetration by air, moisture or vermin.
(d) Exterior surfaces shall be sealed to resist the entrance of rodents.
Subpart E. Testing

280.401. Structural Load Tests.
Every structural assembly tested shall be capable of meeting the Proof Load Test or the ultimate Load Test as follows:
(a) Proof load tests. Every structural assembly tested shall be capable of sustaining its dead load plus superimposed live loads equal to 1.75 times the required live loads for a period of 12 hours without failure. Tests shall be conducted with loads applied and deflections recorded in 1/4 design live load increments at 10-minute intervals until 1.25 times design live load plus dead load has been reached. Additional load shall then be applied continuously until 1.75 times design live load plus dead load has been reached. Assembly failure shall be considered as design live load deflection (or residual deflection measured 12 hours after live load removal) which is greater than the limits set in 280.305(d), rupture, fracture, or excessive yielding. An assembly to be tested shall be of the minimum quality of materials and workmanship of the production. Each test assembly, component or subassembly shall be identified as to type and quality or grade of material. All assemblies, components or subassemblies qualifying under this section shall be subject to continuing qualification testing program acceptable to the Department.
(b) Ultimate load tests. Ultimate load tests shall be performed on a minimum of three assemblies to generally evaluate the structural design. Every structural assembly tested shall be capable of sustaining its total deal load plus live loads increased by a factor of safety consistent with the material being tested. Factors of safety shall be based on nationally recognized standards and approved by the Department. Tests shall be conducted with loads applied and deflections recorded in 1/4 design live load increments at 10-minute intervals until 1.25 times design live load plus dead load has been reached. Additional loading shall then be applied continuously until failure occurs or 1.50 times the factor of safety times the design live load plus the dead load is reached. Assembly failure shall be considered as design live load deflection greater than the limits set in 280.305(d) rupture, facture, or excessive yielding. Assemblies to be tested shall be representative of average quality or materials and workmanship of the production. Each test assembly, compoment, or subassembly shall be identified as to type and quality or grade of material. All assemblies, components, or subassemblies qualifying under this section shall be subject to a periodic qualification testing program acceptable to the Department.
280.402. Test Procedure for Roof Trusses.
(a) Roof load tests. The following is an acceptable test procedure, consistent with the provisions of 280.401, for roof trusses that are supported at the ends and support design loads. Where roof trusses act as support for other members, act as cantilevers, or support concentrated loads, they shall be tested accordingly.
(b) General. Trusses may be tested in pairs or singly in a suitable test facility. When tested singly, simulated lateral support of the test assembly may be provided, but in no case shall this lateral support exceed that which is specified for the completed mobile home. When tested in pairs, the trusses shall be spaced at the design spacing and shall be mounted on solid support accurately positioned to give the required clear span distance (L) as specified in the design. The top and bottom chords shall be braced and covered with the material, with connections or method of attachment, as specified by the completed mobile home.

(1) As an alternate test procedure, the top mhord may be sheathed with 1/4 inch by 12 inch plywood strips. The plywood strips shall be at least long enough to cover the top chords of the trusses at the designated design truss spacing. Adjacent plywood strips must be separated by at least 1/8 inch. The plywood strip shall be nailed with 4d nails or equivalent staples not closer than 8 inches on center along the top chord of one truss only. The bottom chords of the adjacent trusses may be either: (i) Unbraced, (ii) laterally braced together (not cross braced) with 1' x 2' stripping not closer than 24 inches on center nailed with only one 6d nail at each truss, or (iii) covered with the material, with connections or methods of attachment, as specified for the completed mobile home.
(2) Truss deflections will be measured relative to a taut wire running over the support and weighted at the end to insure constant tension or other approved methods. Deflections will be measured at the two quarter points at midspan. Loading shall be applied to the top chord through a suitable hydraulic, pneumatic, or mechanical system, masonary units, or weights to simulate design loads. Load units for uniformly distributed loads shall be separated so that arch action does not occur, and shall be spaced not greater than 12 inches on center so as to simulate uniform loading.

(c) Nondestructive test procedure.
(1) Dead load plus live load. (i) Noting figure A, measure and record initial elevation of the truss in test position at no load. (ii) Apply load units to the top chord of the truss equal to the full dead load of roof and ceiling. Measure and record deflections. (iii) Maintaining the dead load, add live load in approximately 1/4 design live load increments. Measure the deflections after each loading increment. Apply incremental loads at a uniform rate such that approximately one-half hour is required to establish the total design load condition. Measure and record and deflections five minutes after loads have been applied. The maximum deflection due to design live load (deflection measured in step (iii) minus step (ii) shall not exceed L/180, where L is a clear span measured in the same units. (iv) Continue to load truss to dead load plus 1.75 times the design live load. Maintain this loading for 12 hours and inspect truss for failure. (v) Remove the total superimposed live load. Trusses not recovering to at lease the L/180 position within 12 hours shall be considered as failing.
(2) Uplift Loads. This test shall only be required for truss designs which may be critical under uplift load conditions. (i) Measure and record initial elevation of the truss in an inverted test position at no load. Bottom chord of the truss shall be mounted in the horizontal position. (ii) Apply the uplift load as stated in 280.305(c) to the bottom chord of the truss. Measure and record the deflections 5 minutes after the load has been applied. (iii) Continue to load the truss to 1.75 times the design uplift load. Maintain this load for 3 hours and inspect the truss for failure. (iv) Remove applied loads and within three hours the truss must recover to at lease L/180 position, where L is a clear span measured in the same units.
(d) Destructive test procedure.
(1) Destructive tests shall be performed on three trusses to generally evaluate the truss design.
(2) Noting figure A-1, apply the load units to the top chord of the truss assembly equal to full dead load of roof and ceiling. Measure and record deflections. Then apply load and record deflections 1/4 design live load increments at 10-minute intervals until 1.25 times design live load plus dead load has been reached.
(3) Additional loading shall then be applied continuously until failure occurs or the factor of safety times the design live load plus the deal load is reached.
(4) Assembly failure shall be considered as design live load deflection greater than the limits set in 280.305(d), rupture, fracture, or excessive yielding.
(5) The assembly shall be capable of sustaining the dead load plus the applicable factor of safety times the design live load (the applicable factor of safety for wood trusses shall be taken as 2.50).
(e) Trusses qualifying under the nondestructive test procedure. Tests 280.402(c)(1) and (2) (when required), shall be subject to a continuing qualification testing program acceptable to the Department. Trusses qualifying under the destructive test procedures. Tests 280.402(c)(2) (when required), and (d), shall be subject to periodic tests only.


280.403. Standard for Windows and Sliding Glass Doors Used in Mobile Homes.
(a) Scope. This section sets the requirements for prime windows and sliding glass doors used in mobile homes except for windows used in entry doors. Windows so mounted are components of the door and thus are excluded from this standard.
(b) Materials and methods. Any material or method of construction, whether or not provided for in this standard, and any material or method of questioned suitability, proposed for use in manufacture, shall nevertheless conform in performance as outlilned in paragraph (c) of this Section and proof of capability of structural integrity shall be presented. If applicable, units shall comply with the following:
(1) Wood and wood based products.
(i) Wood. Wood parts including plywood and particleboard parts of window units shall have a moisture content of 6 to 12 percent at the time of fabrication. Wood parts, except inside stops and trim shall be manufactured utilizing wet-use adhesive requirements as defined in ASTM D-3110 and preservative treated in accordance with NWMA IS-4.

(ii) Plywood. Plywood parts except for inside stops and trim shall be exterior type plywood and preservative treated in accordance with NWMA IS-4.
(iii) Particleboard. Particleboard parts except for inside stops and trims shall be type-2 particleboard and preservative treated in accordance with NWMA IS-4.
(2) Aluminum.
(i) Alloys. Aluminium shall be of a commercial quality and of proper alloy for window construction, free from defects impairing strength and/or durability, as follows:
Wrought aluminum alloys shall be those in which the alloying elements do not exceed the following maximum limits:

Percent
Silicone 7.0
Magnesium

Manganese 6.0
Chromium
Iron 1.0
Copper .4
Zinc 1.0
Other .5
Aluminum Balance


These limits apply to both bare products and to the core clad products. The cladding of clad products shall be within the same limits except the maximum zinc limit may be 3.0 percent in order to assure that the cladding is anodic to the core. Where aluminum extrusions are used for the main frame and sash or ventilator sections, they shall have a minimum ultimate tensile strength of 22,000 psi and a yield of 16,000 psi.
(ii) Finish. The exposed surface of all aluminum members shall be clean and free from serious surface blemishes. If exposed welded joints are used, they shall be dressed and finished.
(3) Glass. (k) Safety glazing materials, where used, shall meet ANSI Z97.1- 1972. Tempered glass, where used, shall also meet FS DD-G-1403A. (ii) Insulated glass, when used, shall meet or exceed the requirements of Sealed Insulating Glass Manufacturers Association (SIGMA) and shall be permanently identified with the name of the insulating glass manufacturer. (iii) Glass tolerances and areas shall meet or exceed the values shown in the Glass Table below.

Glass Dimensional Tolerances [FNa] and Maximum
Allowable Areas--Sheet Glass
Normal Minimum Maximum Maximum
thickness thickness area [FNb] area [FNb]
(inches) (inches) (square ft) (square ft)
at 15 lb/ft [FN2] at 25 lb/ft [FN2]
18 oz 0.078 11 10
SS .085 13 11
24 oz 108 18 14
DS 115 20 15
3/16 182 40 30
7/32 206 58 37

14 236 72 43

[FNa] For other types of glass see Federal Specification DD-G-451c, dated Jan. 15, 1968.
[FNb] Maximum areas shown are based on minimum glass thickness set forth. Maximum areas shown apply for rectangular lites of annealed glass firmly supported on all 4 sides in a vertical position.
Tabulated areas may be increased as noted for use of tempered, heat strengthened or sealed insulating glass and shall be decreased as noted for use of sandblasted, wire or laminated glass. Glass louvers installed in jalousies shall be not less than 7/32' thick nor longer than 36' and exposed edges shall be seamed, ground or polished.

Adjustment Factors
Relative Resistance to Wind Loads [FN1]
Glass type: Approximate

Relationship
Regular Plate 1.0
Laminated 0.6
Wire 0.5
Heat strengthened 2.0
Fully tempered 4.0
Factory fabricated insulating glass [FN2] 1.5
Rough rolled or patterned surface 1.0
Sand blasted annealed glass 0.4

[FN1] To determine the maximum allowable area for the glass types listed multiply the allowable area established by the appropriate adjustment factor
[FN2] Use thickness of thinner of the two lights, not thickness of unit
(4) Glazing. Any method of glazing conforming to the Performance Requirements (paragraph c of this section) and Material and Methods Requirements (paragraph b of this section) shall be acceptable.

(5) Hardware and Fasteners. All hardware components and fasteners when considered as individual components, whether commercially available, or proprietary, must be capable of performing of the criteria stipulated in Performance Requirements, paragraph (c) of this section.
(c) Performance Requirements. Test procedures as outlined in paragraphs (c) thru (4) of this section are applicable to preproduction prototype units of prime windows and sliding glass doors. Production line units shall be equivalent in design and materials to the tested and passed prototype units and shall also meet the requirements of 280.403(c)(5).
(1) Size of test specimen. Production line units shall have width and height dimensions equal to or less than the corresponding dimensions of the prototype unit tested and passed. No inference of compliance to these requirements is to be made for products exceeding the size of the tested and passed prototype.
(2) Structural performance test. (i) Zone I. There shall be no glass breakage, permanent deflection or any other condition which would cause the specimen to be inoperable after being subjected to an exterior pressure, 15 pounds per square foot. The test methods applicable to this requirement shall be ASTM E-330. (ii) Zone II. There shall be no glass breakage, permanent deflection or any other condition which would cause the specimen to be inoperable after being subjected to exterior pressure of 25 pounds per square foot. The test method applicable to this requirement shall be ASTM E-330. (iii) Interior pressure. There shall be no glass breakage, permanent deflection or any other condition which would cause the specimen to be inoperable after being subjected to an interior pressure equal to 1/2 the requirements in either paragraphs (c)(2)(i) or (c)(2)(ii). The test method applicable to this requirement shall be ASTME-330 except that no artificial means of containing pressure shall be allowed. Should pressure not be obtainable due to lack of air the testing agency will report the pressure achieved, the theoretical air flow supplied to the unit, and certify that no additional flow from the equipment in use was available. Laboratory equipment used for this test must be capable of developing 10 x air flow determined in 280.403(c)(3).
(3) Air infiltration test. Air infiltration shall not exceed 0.50 CFM per square foot of window area when tested in accordance with ASTME-283 at an exterior pressure differential of 1.567 pounds per square foot (0.30' of water pressure).
(4) Water resistance test. No leakage shall pass the interior face of the test specimen at a test pressure of 2.86 psf (0.55' water pressure) when tested in accordance with ASTM E-547 with a test period consisting of four cycles, each cycle consisting of five minutes with pressure released, during which the water spray will be continuously applied. (i) For the purpose of compliance with paragraph (c)(4), all units which may have exterior screens, shall be tested first with screens in place and thereafter with screens removed. (ii) For the purpose of compliance with paragraph (c)(4), penetration, as referenced in ASTM E-331-70, paragraph 4.3, shall not include drops passing the interior face by energy developed in the bursting of sill drain system bubbles created by a pressure differential applied to the exterior face of the specimen.
(5) Production Line Units. Production line units of prime windows and sliding glass doors shall comply with: (i) The structural performance test to the zone limit certified in paragraph (c)(2) of this section and; (ii) the air infiltration test in paragraph (c)(3) of this section and; (iii) the water resistance test in paragraph (c)(4) of this screen except that the test pressure shall be 1.56 psf (0.30' water column) and the water application rate shall be 2.5 GPH, per square foot of window surface area, all other parameters being the same as set forth in paragraph (c)(4) of this section.
(d) Test sequence. The sequence of tests shall be performed as they are listed above except that Structural Performance Test to Zone I (15 PSF) exterior pressure may be followed by Zone I interior pressure (7.5 PSF), which may be followed by the Air Infiltration Test, which may be followed by the Water Resistance Test, which may be followed by the Structural Performance Test to Zone II (25 PSF) exterior pressure, which may be followed by the Zone II interior pressures (12.5 PSF), which may be followed by the Air Infiltration Test, which may be followed by the Water Resistance Test. The Air Infiltration Test may be performed after the Water Resistance providing all sealed areas are thoroughly dried.
(e) Screens.
(1) Screen, when specified, shall be provided with fastening devices, suited particularly for application to the specific window for which they are intended, and be of sufficient strength to perform satisfactorily.
(2) Insect screening shall be of a material compatible with aluminum and shall meet CS 138-55, 'Insect Wire Screening,' FS RR-W-365. 'Screening, Wire, Insect,' CS 248-64, 'Vinyl Coated Glass Fibre Insect Screening and Louver Cloth,' or FS L-S-125a 'Screening, Non Metallic Insect.'
(f) Assembly. Windows shall be assembled in a secure and workmanlike manner to perform as hereinafter specified and to assure neat and weather tight construction. A permanent-type water-tight joint shall be made at the junction of the sill and side frame members.
(g) Shipping. Units may be shipped either as a subassembly unit or a completely assembled unit but not as a KD or open unit. A KD unit is a unit that is complete in its entirety with the exception of glass, glazing material, or screen, which is shipped in disassembled condition and later assembled and glazed according to the instructions of the manufacturer and utilizing all of the components supplied or specified by the manufacturer.
(1) An open unit is a unit that is complete in its entirety with the exception of glass, glazing materials, or screen, which is shipped in an assembled condition and later glazed according to the instruction of the manufacturer, utilizing all of the components supplied by the manufacturer.
(2) A subassembly unit is a unit that is complete in its entirety including the glazing of glass or other glazing panels into their respective fixed or moving sash frames, which is shipped with such glazed panels separate from each other or from any master frame, which master frame may be either disassembled or assembled. The connection of such master frame to glazed, fixed, or moving panels is to take place later according to the instructions of the manufacturer utilizing all of the components supplied by the manufacturer.
(3) A completely assembled unit is one that is complete in its entirety and is shipped with all parts and subassemblies in complete connection with each other and no separate pieces.
(h) Permanent identification.
(1) As identification, each unit shall bear a certification label containing a code number traceable to the manufacturer through the certifying agency or the name of the manufacturer or brand name together with the city and state location of the manufacturer or main office of the manufacturer.
(2) The label shall be of a permanent-type designed to discourage easy removal, shall be legible and shall remain legible under normal operating conditions for a period of not less than five years from date of product installation.
(3) Acceptable means of identification are, but are not limited to, the following: Embossed, stamped, cast or molded characters becoming an integral part of the material on which they are located; flexible color-fast and durable labels, decals, stickers, etc., affixed with a permanent-type adhesive; or rigid metal or plastic name plates affixed mechanically or with a permanent-type adhesive.
(4) Location of the label shall be such that it is accessible for normal direct viewing purposes from the interior side of the product, after the unit is installed, without the necessity of product disassembly. Identification located only on the glass or screen, shall not be acceptable.
(i) Certification. The manufacturer shall show evidence of continued compliance by affixing a quality certification label to the product in accordance with ANSI Z34.1, 'American National Standard Practice for Certification Procedures.' In determining certifiability under this section, compliance shall consist of preproduction specimen testing in accordance with each and every requirement of this section followed by an inplant inspection and production unit testing system consisting of a minimum of two such inspections per year by an independent quality assurance agency.
280.404. Standard for Egress Windows for Use in Mobile Homes.
(a) Scope and purpose. The purpose of this section is to establish the requirements for the design, construction, and installation of windows and approved devices intended to be used as an emergency exit during conditions encountered in a fire or similar disaster.
(b) Requirements.
(1) Installation. Window manufacturers shall provide the home manufacturer with written installation instructions.
(2) Performance. The egress window including auxiliary frame and seals, if any, shall meet the requirements of 280.403 'Standard for Windows and Sliding Glass Doors Used in Mobile Homes.'
(3) Dimensions. (i) All egress windows shall have a minimum clear dimension of 22 inches when determined in accordance with Test A paragraph (d)(1) of this section. (ii) All egress windows shall have a minimum clear opening of 5 square feet when determined in accordance with Test B, paragraph (d)(2) of this section.
(4) Operational. (i) Operating instructions shall be applied to each egress window and carry the legend 'Do Not Remove.' In addition, the instructions should include a reminder to remove all shipping clips on screens, storm windows, and other appurtenances for exiting purproses. (ii) The number of locks and latches shall not exceed 2, not including the 4 appurtenance attachment mechanisms permitted by paragraph (c)(2)(i) of this section. (iii) Locks, latches, lifting and sliding operational forces shall not exceed a force of 20 pounds when tested in accordance with Test C, paragraph (d)(3) of this section. (iv) Any handle or latch required to operate the emergency egress provisions of the window shall be attached in the factor by either a permanent method or a mechanical method which requires a tool not commonly available in the home, unless removal of the latch or handle will in no way limit the effectiveness of the egress provision. (v) Any window whose egress provisions are dependent on the operation of a rotary operation is unacceptable.
Example: Awning windows utilizing a single vent for egress and requiring a rotary operator for activation is unacceptable, whereas an awning window set in a separate frame whose activation requires only a 180° twist of the lock to allow egress is acceptable even though a rotary operator is present for normal operation.
(c) Appurtenances.

(1) The addition or inclusion of screens, storm windows, or other appurtenances shall not encroach upon the dimensional requirements set forth in paragraph (b)(3).
(2) Any mechanism used to attach an appurtenance such as a screen or storm window to the window shall meet the following requirements unless the appurtenance meets the requirements of paragraph (c)(3): (i) The number of mechanisms shall not exceed 4 and; (ii) The operating force of the mechanisms shall not exceed 5 pounds tested in accordance with Test D paragraph (d)(4) and; (iii) The mechanisms shall be designed so that that cannot be misapplied utilizing normal household tools such as screwdrivers, pliers, and wrenches exceeding the aforementioned forces; and (iv) The surface to which the operating force is applied shall have a minimum cross-sectional area of 0.25 square inches.
(3) If an appurtenance such as a screen or storm window is attached to the window in such a manner that it need not be removed or disengaged in any way in order to effect a fully opened exit, the requirements of paragraph (c)(2) need not be met.
(4) The operating instructions detailed in paragraph (b)(4)(i) shall include instructions on the required removal and replacement of any screen and/or storm sash appurtenance.
(d) Test methods.
(1) Test Method A--Minimum Dimensions. The minimum dimension of 22 in. required by paragraph (b)(3)(i) shall be tested as follows: When the window is in the final position for egress, a 22 in. dowel shall be passed through the opening at the point of its least dimension while contacting only one point of the window frame, at either the horizontal or vertical orientation of the dowel.
Example: In a horizontally opening window (sliding or rolling), the minimum dimension requirement may be met as follows: When the window is in the final position for egress, place one end of the dowel perpendicularly against the portion of the main frame side (bottom) projecting furthest towards the center of the opening, and pass the dowel through the opening in a horizontal (vertical) plane without touching any portion of the device except the main frame side (bottom) on which it pivoted.
(ii) Example: Any type of window may be mounted in a side, bottom, or hinged or pop-out egress frame which in the fully opened position meets the minimum dimension and area requirements.
(2) Test Method B--Minimum Area. The minimum area requirement of 5 square feet contained in paragraph (b)(3)(ii) shall be determined by multiplying the minimum dimension (which may exceed 22 in.) by the clear dimension measured perpendicularly to the minimum dimension and in the plane of the window main frame.
(i) Example: In a vertically operating window whose minimum dimension is from the main frame bottom to that portion of the operating vent projecting furthest toward the horizontal center line of the egress opening when in the fully opened position, the minimum area shall be determined by multiplying the dimension by the inside side-to-side dimension.
280.509. Criteria in Absence of Specific Data.
In the absence of specific data, for purposes of heat-loss/gain calculation, the following criteria shall be used:
(a) Infiltration Heat Loss. In the absence of measured infiltration heat loss data, the following formula shall be used to calculate heat loss due to infiltration and intermittently operated fans exhausting to the outdoors. The perimeter calculation shall be based on the dimensions of the pressure envelope.
Infiltration Heat-Loss = 0.7 (T) (ft. of perimeter), BTU/hr. where: T-70 minus the heating system capacity certification temperature stipulated in the Heating Certificate, in F.
(b) Framing areas.

Wall 15 percent of wall area less
windows and doors.
Floor and Ceilling 10 percent of the area.


(c) Insulation compression. Insulation compressed to less than nominal thickness hall have its nominal R-values reduced for that area which is compressed in accordance with the following graph:


When insulation is installed over the framing members the thermal performance of the insulation is reduced due to compression to the framing members. The Resistance value of the insulation between the framing members is reduced by 12.5 percent for framing members 16' O.C., 8.5 percent for framing members 24' O.C., and 4 percent for framing members 16' O.C., 8.5 percent for framing members 24' O.C., and 4 percent for framing members 48' O.C.
(d) Air supply ducts within floor cavity. Air supply ducts located within a floor cavity shall be assumed to be heating or cooling the floor cavity to living space temperatures unless the duct is structurally isolated by the framing system or thermally insulated from the rest of the floor cavity with a thermal insulation at least equal to R-4.
(e) Air supply ducts within ceiling cavity. Where supply ducts are located in ceiling cavities, the influence of the duct on cavity temperatures shall be considered in calculating envelope heat loss or heat gain.
(f) The supply duct loss (and/or heat gain where applicable-See 280.511) shall be calculated using the actual duct surface area and the actual thickness of insulation between the duct and outside of the mobile home. If there is an air space of at least 1/2 inch between the duct and the insulation, heat loss/gain need not be calculated if the cavity in which the duct is located is assumed to be at living space temperature. The average temperature inside the supply duct, including ducts installed outside the mobile home, shall be assumed to be 130° F for purposes of calculation of heat loss and 60° F for heat gain.
(g) Return air cavities. Cavities used as return air plenums shall be considered to be at liging space temperature.
280.510. Heat Loss Certificate.
The mobile home manufacturer shall permanently affix the following 'Certificate' to an interior surface of the home that is readily visible to the homeowner. The 'Certificate' shall specify the following:
(a) Heating zone certification. The design at which the mobile home heat loss complies with 280.506(a).
(b) Outdoor certification temperature. The lowest outdoor temperature at which the installed heating equipment will maintain a 70° F temperature inside the home without storm sash or insulating glass for Zone I and with storm sash or insulating glass or Zones II and III and complying with 280.508 and 280.509.
HEATING CERTIFICATE

Home Manufacturer.............................................
Plant Location................................................
Home Model....................................................

(Include Winter Climate Map)
This mobile home has been thermally insulated to conform with the requirements of the Federal Mobile Home Construction and Safety Standards for all locations with climatic Zone _____.
Heating Equipment Manufacturer................................
Heating Equipment Model.......................................
The above heating equipment has the capacity to maintain an average 70° temperature in this home at outdoor temperatures of ____F.
To maximize furnace operating economy, and to conserve energy, it is recommended that this home be installed where the outdoor winter design temperature (97-1/2%) is not higher than ____ degrees Fahrenheit. [FN1]
The above information has been calculated assuming a maximum wind velocity of 15 MPH at standard atmospheric pressure.
[FN1] The temperature to be specified shall be 20° F or 30% of the design temperature difference, whichever is greater, added to the temperature specified as the heating system capacity certification temperature without storm windows or insulating glass for Zone I and with storm windows or insulating glass for Zones II and III. Design temperature difference is 70 minus the heating system capacity certification temperature in degrees Fahrenheit.
280.511. Comfort Cooling Certificate and Information.
(a) The mobile home manufacturer shall permanently affix a 'Comfort Cooling Certificate' to an interior surface of the home that is readily visible to the home owner. This certificate may be combined with the heating certificate required in 280.510. The manufacturer shall comply with one of the following three alternatives in providing the certificate and additional information concerning the cooling of the mobile home:
(1) Alternative I. If a central air conditioning system is provided by the home manufacturer, the heat gain calculation necessary to properly size the air conditioning equipment shall be in accordance with procedures outlined in Chapter 22 of the ASHRAE Handbook of Fundamentals, with an assumed location and orientation. The following information shall be supplied on the Comfort Cooling Certificate:
Air Conditioner Manufacturer.................................
Air Conditioner Model........................................
Certified Capacity ___BTU/Hr. in accordance with the appropriate Air Conditioning and Refrigeration Institute Standards.
The central air conditioning system provided with this home has been sized, assuming an orientation of the front (hitch) end of the home facing ____ and is designed on the basis of a 75° F indoor temperature and an outdoor temperature of ____ F dry bulb and ____ F wet bulb.
EXAMPLE ALTERNATE 1

COMFORT COOLING CERTIFICATE

Mobile Home Mfg. .............................................
Plant Location ...............................................

Mobile Home Model ............................................ (continued)