A. Construction Materials and Methods: These requirements specify minimum acceptable construction materials and methods. Other materials and methods not specified herein may be approved for use by the Building Official upon the submission of evidence satisfactory to him that their performance in use will be at least equivalent to that of the materials and methods specified herein. It shall be required that such evidence include adequate reports and test data from a recognized testing laboratory, or proven and authoritative service records, or analysis of performance made in accordance with well established principles of mechanics.
B. Loads:
1. All parts of dwellings and accessory buildings and structures shall be designed, constructed and maintained to support safely their own weight and all other loads and forces to which they may be subjected.
2. Assumed minimum live loads (uniformly distributed) for design purposes.
a. Ceiling or attic floor joists, no storage - none; attic floors, limited storage only - twenty (20) pounds per square foot.
b. Girders - Dead loads of floor, partition and ceiling constructions, plus fifty percent (50%) of assumed live loads of floors plus combined dead and live loads of roof.
c. Roofs, either pitched or flat - twenty (20) pounds per square foot normal to the roof surface.
3. Wind loads:
a. On vertical faces - twenty (20) pounds per square foot horizontally, any direction.
b. Roofs or parts with slopes greater than thirty degrees (30°) - twenty (20) pounds per square foot acting inward normal to surface, on windward slope only.
c. Lifting forces - twenty (20) pounds per square foot. To prevent sliding or overturning, anchor roofs to walls and columns, and walls and columns to foundations.
C. Special Conditions and Tests: When special conditions exist or arise during construction which necessitate additional precautions, the Building Official may require work in excess of these requirements.
D. Vapor Barriers:
1. Definition: A material having a vapor transmission rate of one point five (1.5) perm or less. Generally acceptable are:
a. Fifty five (55) pounds per one hundred eight (108) square feet of smooth roofing.
b. Foil or foil backed board.
c. Duplex laminated papers 30-60-30.
d. Duplex papers coated with metal oxides.
e. Insulation backup paper-treated.
2. Ceiling: Where unheated spaces above, install independent vapor barrier or one integral with insulating material immediately above ceiling interior finish.
3. Sidewalls: When exterior coefficient of heat transmission is not more than sixteen one-hundredths (0.16) B.T.U. per square foot, per degree temperature difference. Install immediately back of interior wall finish.
4. Crawlspace: See subsection 8-1A-2-1H5 of this Article.
5. Vapor barrier to be applied tightly against any electrical outlets, registers or framed openings.
E. Thermal Insulations:
1. Unheated Crawlspaces:
a. Insulation of floors (any one of the following):
(1) Foil reflective type on both sides between joists with two inches (2") air space maintained between bottom of floor and foil. Install so that there are no openings at ends of joists.
(2) One-half inch (1/2") rigid insulation board fastened to bottom of floor joists. Install so that there are no openings at ends of joists.
(3) Any insulation better than that above, i.e., one inch (1") blanket.
b. Insulation of ducts and pipes located in crawlspace:
(1) Warm air ducts and plenum shall be covered with insulation material, minimum thickness two inches (2").
(2) Return air ducts shall be covered with insulation material, minimum thickness one inch (1").
(3) Sewer and water supply shall be covered with insulation material, minimum thickness one inch (1").
2. Heated Crawlspaces:
a. Install insulation, minimum one inch (1") thick, on all surfaces of foundation walls that are adjacent to crawlspace.
b. Insulation shall be waterproof and noncapillary, inorganic and termite and fungi resistant.
c. Insulation shall be installed to extend up to underside of sub-flooring, to extend down to six inches (6") above ground and to be fastened to foundation walls.
3. Insulation for exterior perimeters of concrete floor slabs:
a. At least one inch (1") thickness at edges.
b. Where heating ducts in floor increase to one and one-half inches (11/2") at slab edge.
c. Extend insulation down along inside face of foundation wall for a distance of at least eighteen inches (18").
d. Insulation material requirements shall be inorganic, waterproof and noncapillary, and termite and fungi resistant.
4. Ceiling Insulation:
a. Not less than six inches (6") net thickness of fire resistive, flameproof insulation.
b. Foil of equivalent rating acceptable.
5. Heating Requirements:
a. Provide heating unit capable of heating dwelling from minus ten degrees (-10°) Fahrenheit to seventy two degrees (72°) Fahrenheit at fifteen (15) miles per hour outside wind with heat loss calculated in accord with American Society of Heating and Ventilating Engineers standards.
b. Heating unit shall be constructed and installed in strict accord with the applicable current published standards, requirements and recommendations of the National Fire Protective Association, National Board of Fire Underwriters, American Standards Association, and the American Society of Mechanical Engineers. Labeling and listing by following shall be accepted as conforming with equipment design standards: Underwriters Laboratories, Inc., American Gas Association, or American Society of Mechanical Engineers.
c. Clearance shall be provided for all heating equipment for access, repair and maintenance.
d. Smoke pipes where extreme heat is hazardous to human occupancy shall be insulated from furnace to chimney with a minimum of one-fourth inch (1/4") of asbestos material.
e. Insulation of all heat producing devices shall be such that temperature rise of surrounding frame construction will not exceed one hundred sixty degrees (160°) Fahrenheit.
6. Wall Insulation:
a. Not less than three-fourths inch (3/4") net thickness of fire resistive, flameproof insulation between furring strips on exterior masonry walls.
b. Not less than three and five-eighths inch (35/8") net thickness of fire resistive, flameproof insulation between studding on exterior frame walls. (Ord. 0-71-12, 3-11-71)
F. Alternative Material Construction: The following provisions shall apply with respect to the use of alternative material construction for air conveyance duct work in residential structures:
1. All air conveyance for heating, cooling and conditioning purposes within a residential structure or dwelling shall take place within approved, noncombustible duct work. The construction of these ducts shall be of sheet-metal. Flexible nonmetal ducts (where permitted) shall be installed in accordance with the manufacturers installation instructions and shall meet or exceed the following requirements:
a. UL Class 1 Flexible Air Duct – U1 181 rated,
b. NFPA 90A-90B,
c. SMACNA Standards and
d. BOCA Basic Mechanical Code.
2. Sheet metal duct work shall be installed in accordance with the following minimum requirements:
a. BOCA Basic Mechanical Code and
b. SMACNA standards.
3. The maximum permitted length of each flexible nonmetal duct shall be six feet (6'), and shall only be installed where, in the opinion of the building officer, the use of sheet metal elbows, fittings and bends would greatly diminish the air movement quality of the installation. (Ord. 0-89-338, 5-11-1989)