Chapter 14.08 BUILDING CODE

Chapter 14.08
BUILDING CODE

Sections

14.08.010 Short title – IBC adopted.

14.08.020 Amendments adopted.

14.08.030 Applications for building permit – Other filings required.

14.08.040 Optional method of obtaining prior approvals – Agreement regarding vested rights.

14.08.050 IBC Section 105.5 amended – Expiration of permit.

14.08.060 IBC Section 105.3.1 and 105.3.2 amended – Action on application and time limit of application.

14.08.070 Use and occupancy.

14.08.080 IBC Section 501.2 amended – Premises identification.

14.08.090 Assurance device for building permit – Requirements.

14.08.100 IBC Section 903.2.1.1, 903.2.1.3, 903.2.1.4, 903.2.3, 903.2.6, 903.2.8, 903.2.8.1, and 705.1 amended – Fire protection systems.

14.08.110 IBC Section 705.1 amended – Fire walls.

14.08.120 IBC Section 3106 amended – Special construction – Marquee.

14.08.130 Fire protection for multiple townhomes.

14.08.140 Washington State Indoor Air Quality Code Section 303.4.1.5 amended.

14.08.150 International Property Maintenance Code (IPMC) amended.

14.08.160 Manufactured housing.

14.08.170 Modular housing.

ARTICLE I. SOUND CONTROL REQUIREMENTS

14.08.180 Purpose.

14.08.190 Provisions.

14.08.200 Intent.

14.08.210 Application to existing buildings.

14.08.220 Details.

14.08.230 Modifications and alterations.

14.08.240 Fees.

14.08.250 Design requirements.

14.08.260 Seattle-Tacoma International Airport noise areas.

14.08.270 Specific construction requirements for Areas 1 and 2.

14.08.280 Air leakage for all buildings.

14.08.290 Compliance – Area 1.

14.08.300 Exterior walls – Area 1.

14.08.310 Exterior windows – Area 1.

14.08.320 Exterior doors – Area 1.

14.08.330 Roofs – Area 1.

14.08.340 Ceilings – Area 1.

14.08.350 Floors – Area 1.

14.08.360 Ventilation – Area 1.

14.08.370 Compliance – Area 2.

14.08.380 Exterior walls – Area 2.

14.08.390 Exterior windows – Area 2.

14.08.400 Exterior doors – Area 2.

14.08.410 Roofs – Area 2.

14.08.420 Ceilings – Area 2.

14.08.430 Floors – Area 2.

14.08.440 Ventilation – Area 2.

14.08.010 Short title – IBC adopted.

This chapter is known as and may be referred to as the building code. Except as amended, added to, or excepted in this chapter, Chapter 51-50 WAC, the International Building Code (IBC), is adopted by reference as presently constituted or as may be subsequently amended, added to, or excepted as though fully set forth in this chapter. [Ord. 1407 § 26, 2007.]

14.08.020 Amendments adopted.

The amendments, additions, and exceptions to the International Building Code, as adopted by this chapter, are adopted and shall be applicable within the city. [Ord. 1407 § 27, 2007.]

14.08.030 Applications for building permit – Other filings required.

(1) At the time of filing a building permit application, the applicant shall submit all required information together with any application form and applicable fees therefor, for any of the following:

(a) Design review;

(b) Shorelines substantial development permit;

(d) Development exceptions for environmentally critical areas;

(e) Environmental review (SEPA).

(2) No building permit application shall be accepted without the required information, completed application and applicable fees.

(3) When the planning, building and public works director makes a determination that certain improvements including, but not limited to, curbs, gutters, sidewalks, driveways across sidewalks, piped storm drainage, retaining walls, street illumination, landscaping, slope protection, and underground utilities are required at some future date by existing ordinance(s), no building permit application shall be approved by the building official for any proposed project unless the building permit application is accompanied by a properly executed local improvement district (LID) covenant that has been recorded at the King County department of records.

(4) The filing of a complete building permit application for a proposed project, which project is in compliance with applicable state law and the codes, ordinances, and regulations of the city in effect at the time of such filing, shall establish a vested right, if a building permit is issued, to proceed with construction of the proposed project in accordance with such then-existing codes, ordinances, and regulations; provided, however, such proposed project may nonetheless be conditioned or denied by the city under the State Environmental Policy Act. For the purpose of this section, a “complete building permit application” means an application which contains all information required to be submitted by any applicable provisions of this code, including, but not limited to, all information required to be submitted by subsection (1) of this section. [Ord. 1407 § 28, 2007.]

14.08.040 Optional method of obtaining prior approvals – Agreement regarding vested rights.

(1) An applicant may apply for a design review approval, a shorelines substantial development permit, environmental review (SEPA), or a land clearing, grading, or filling permit prior to filing an application for a building permit, upon the following terms and conditions:

(a) The filing of an application for any of the approvals referred to in this section prior to the filing of a valid and complete application for a building permit shall not establish or create a vested right to proceed with construction of any proposed project in accordance with the codes, ordinances, and regulations existing at the time of the filing of such application, or at any time thereafter prior to the filing of a valid and complete building permit application.

(b) An applicant who elects to take advantage of the provisions of this section shall, at the time of making application for the approvals referred to in this subsection, execute an agreement with the city that the acceptance and processing of such application shall in no way establish or create a vested right to proceed with construction of any proposed project in accordance with the codes, ordinances, or regulations existing at the time of filing of such application, or at any time thereafter prior to the filing of a valid and complete building permit application.

(c) The provisions of this section do not apply to grading or filling done in preparation for the construction of a single home.

(2) An applicant who elects to take advantage of the provisions of this section may at any time elect to file a complete building permit application, notwithstanding that the approval applied for under subsection (1) of this section has not previously been obtained. [Ord. 1407 § 29, 2007.]

14.08.050 IBC Section 105.5 amended – Expiration of permit.

Every permit issued shall become invalid unless the work on the site authorized by such permit is commenced within 180 days after its issuance, or if the work authorized on the site by such permit is suspended or abandoned for a period of 180 days after the time the work is commenced. The building official is authorized to grant, in writing, one or more extensions of time, for periods not more than 180 days each. The extension shall be requested in writing and justifiable cause demonstrated. [Ord. 1407 § 30, 2007.]

14.08.060 IBC Section 105.3.1 and 105.3.2 amended – Action on application and time limit of application.

Applications for which no permit is issued within 180 days following the date of application filing shall expire by limitation, and plans and other data submitted for review may thereafter be returned to the applicant or destroyed by the building official. The building official may extend the time for action by the applicant for a period not exceeding 180 days on request by the applicant showing that circumstances beyond the control of the applicant have prevented action from being taken. No application shall be extended more than once. In order to renew action on an application after expiration, the applicant shall reapply and pay a new plan review fee.

The building official shall extend the life of an application if any of the following conditions exist:

(1) Compliance with a declaration of significance under the State Environmental Policy Act provisions is in progress; or

(2) Any other city review is in progress, provided city staff determine that the review is proceeding to a timely final city decision; or

(3) Litigation against the city is in progress, the outcome of which may affect the validity of any permit issued pursuant to such application. [Ord. 1407 § 31, 2007.]

14.08.070 Use and occupancy.

No building or structure shall be used or occupied, and no change in the existing occupancy classification of a building or structure or portion thereof shall be made until the building official has issued a certificate of occupancy therefor as provided herein.

Exception: Group U Occupancies.

Issuance of a certificate of occupancy shall not be construed as an approval of a violation of the provisions of this code or of other ordinances of the jurisdiction. Certificates presuming to give authority to violate or cancel the provisions of this code or other ordinances of the jurisdiction shall not be valid. [Ord. 1407 § 32, 2007.]

14.08.080 IBC Section 501.2 amended – Premises identification.

Section 501.2 of the International Building Code, as adopted by this chapter, is amended to read as follows:

Premises identification. Approved numbers or addresses shall be provided for new buildings, existing buildings and on construction sites in such a position as to be clearly visible and legible from the street or roadway fronting the property. Letters or numbers shall be a minimum 3 inches (76 mm) in height and stroke of minimum 0.5 inch (12.7 mm) of a contrasting color to the background itself.

[Ord. 1407 § 33, 2007.]

14.08.090 Assurance device for building permit – Requirements.

Before issuing any building permit the city shall require the applicant to execute and file with the city a cash bond or in a form approved by the city manager in such reasonable sum and with the securities as the building official may specify, conditioned that the applicant will pay any and all damages that may be recovered against the city by any person on account of injury to persons or property occasioned by or in any manner resulting from the issuance of the permit or by reason of any act or thing done pursuant thereto, or from the occupancy or disturbance of any street or sidewalk in the city and also to save, keep, and defend the city free from all such damages and costs as may be incurred in defending any such claim, and/or further conditioned that the applicant shall pay to the city the cost of repairing any and all damage which may be done by the applicant or his/her agents to the streets, utilities, or property of the city during or pursuant to the work covered by such permit. [Ord. 1407 § 34, 2007.]

14.08.100 IBC Section 903.2.1.1, 903.2.1.3, 903.2.1.4, 903.2.3, 903.2.6, 903.2.8, 903.2.8.1, and 705.1 amended – Fire protection systems.

Section 903 of the IBC, as adopted by this title, is amended to read as follows:

Fire Sprinkler Systems.

IBC 903.2.1.1

(1) Group A-1. An automatic sprinkler system shall be provided for Group A-1 occupancies where the fire area exceeds five thousand (5,000) square feet;

IBC 903.2.1.3

(1) Group A-3. An automatic sprinkler system shall be provided for Group A-3 occupancies where the fire area exceeds five thousand (5,000) square feet;

IBC 903.2.1.4

(1) Group A-4. An automatic sprinkler system shall be provided for Group A-4 occupancies where the fire area exceeds five thousand (5,000) square feet;

IBC 903.2.3

(1) Group F-1. An automatic sprinkler system shall be provided throughout all buildings containing a Group F-1 occupancy where one of the following conditions exist:

(1) Where a Group F-1 fire area exceeds 5,000 square feet;

(3) Where the combined area of all Group F-1 fire areas on all floors, including any mezzanines, exceeds 5,000 square feet.

IBC Section 903.2.6 Group M. An automatic sprinkler system shall be provided throughout buildings containing a Group M occupancy where one of the following conditions exists:

(1) Where a Group M fire area exceeds 5,000 square feet;

(3) Where the combined area of all Group M fire areas on all floors, including any mezzanines, exceeds 5,000 square feet.

IBC Section 903.2.8 Group S-1. An automatic sprinkler system shall be provided throughout all buildings containing a Group S-1 occupancy where one of the following conditions exist:

(1) Where a Group S-1 fire area exceeds 5,000 square feet;

(3) Where the combined area of all Group S-1 fire areas on all floors, including any mezzanines, exceeds five thousand (5,000) square feet.

IBC Section 903.2.8.1 Repair Garages. An automatic sprinkler system shall be provided throughout all buildings used as repair garages in accordance with the International Building Code, as follows:

(1) Buildings two or more stories in height, including basements, with a fire area containing a repair garage exceeding five thousand (5,000) square feet.

(2) One-story buildings with a fire area containing a repair garage exceeding five thousand (5,000) square feet.

[Ord. 1407 § 35, 2007.]

14.08.110 IBC Section 705.1 amended – Fire walls.

Section 705.1 of the International Building Code, as adopted by this chapter, is amended by the addition of the following subsection to read as follows:

Fire walls as specified in Section 702 and described in Section 705.1 of the International Building Code shall not be used to reduce calculation of floor areas in this chapter.

[Ord. 1407 § 36, 2007.]

14.08.120 IBC Section 3106 amended – Special construction – Marquee.

Section 3106 of the IBC, as adopted by this chapter, is amended to read as follows:

A Marquee is a permanent roofed structure attached to and supported by the building, providing protection from the weather elements, but does not include a projecting roof. For the purposes of this chapter, a freestanding permanent roof-like structure providing protection from the weather elements, such as a service station gas pump island, shall also be considered a marquee.

[Ord. 1407 § 37, 2007.]

14.08.130 Fire protection for multiple townhomes.

A 13R fire suppression system shall be installed in all multiple townhome structures in excess of four common wall dwelling units. [Ord. 1407 § 38, 2007.]

14.08.140 Washington State Indoor Air Quality Code Section 303.4.1.5 amended.

Washington State Indoor Air Quality Code Section 303.4.1.5 shall be amended as follows:

Outdoor Air Inlets: Outdoor air shall be distributed to each habitable room by individual outdoor air inlets. Where outdoor air supplies are separated from exhaust points by doors, provisions shall be made to ensure air flow by installation of distribution ducts, undercutting doors, installation of grilles, transoms, or similar means where permitted by the International Building Code. Doors shall be undercut to a minimum of 1/2-inch above the surface of the finished floor covering.

(1) Individual room outdoor air inlets shall:

(a) Have controllable and secure openings;

(b) Be sleeved or otherwise designed so as not to compromise the thermal properties of the wall or window in which they are placed;

(c) Provide not less than 4 square inches of net free area of opening for each habitable space. Any inlet or combination of inlets which provide 10 cfm at 10 Pascals as determined by the Home Ventilating Institute Air Flow Test Standard (HVI 901 [November 1996]) are deemed equivalent to 4 square inches net free area.

(2) Inlets shall be screened or otherwise protected from entry by leaves or other material. Outdoor air inlets shall be located so as not to take air from the following areas:

(a) Closer than 10 feet from an appliance vent outlet, unless such vent outlet is 3 feet above the outdoor air inlet.

(b) Where it will pick up objectionable odors, fumes or flammable vapors.

(d) A room or space having any fuel-burning appliances therein.

(e) Closer than 10 feet from a vent opening of a plumbing drainage system, unless the vent opening is at least 3 feet above the air inlet.

(f) Attics, crawl spaces, or garages.

[Ord. 1407 § 39, 2007.]

14.08.150 International Property Maintenance Code (IPMC) amended.

The International Property Maintenance Code (IPMC), as adopted by Section 101.4.5 of the International Building Code, is hereby amended, added to, and excepted as follows:

(1) Any reference to an appeal of any administrative action regarding this chapter shall be in accordance with the city of Des Moines Hearing Examiner Code, chapter 18.94 DMMC, or with procedures set forth in chapter 1.24 DMMC for civil infractions or chapter 1.28 DMMC for civil violations and penalties.

(2) The following sections of the 2006 IPMC, or the corresponding section of any updated or amended version of the IPMC, are removed in their entirety and not adopted:


111	Means of Appeal
302.2	Grading and Drainage
302.5	Rodent harborage
302.8	Motor vehicles
302.9	Defacement of property
304.2	Protective treatment
304.3	Premises identification
304.13.2	Openable windows
304.14	Insect screens
304.15	Exterior Doors
304.17	Guards for basement windows
304.18	Building security
305.3	Interior surfaces
305.6	Interior doors
307	Rubbish and Garbage
308	Extermination
404.4.1	Room area
404.5	Overcrowding
404.6	Efficiency unit
604.2	Electrical appliance service

(3) That portion of Section 103.5 of the 2006 IPMC, or the corresponding section of any updated or amended version of the IPMC, that is left for the decision of the local jurisdiction shall read as follows:

The fees for activities and services performed by the department in carrying out its responsibilities under this code shall be set by the City Manager.

(4) That portion of Section 302.4 of the 2006 IPMC, or the corresponding section of any updated or amended version of the IPMC, that is left for the decision of the local jurisdiction shall read as follows:

All premises and exterior property shall be maintained free from weeds or plant growth in excess of twelve (12”) inches. All noxious weeds shall be prohibited. Weeds shall be defined as all grasses, annual plants and vegetation, other than trees or shrubs, provided; however, this term shall not include cultivated flowers and gardens.

(5) The last sentence of Section 304.9 of the 2006 IPMC, or the corresponding section of any updated or amended version of the IPMC, is not adopted so that Section 304.9 shall read only:

All overhang extensions, including but not limited to canopies, marquees, signs, metal awnings, fire escapes, standpipes and exhaust ducts shall be maintained in good repair and be properly anchored so as to be kept in a sound condition.

[Ord. 1407 § 40, 2007.]

14.08.160 Manufactured housing.

All manufactured homes, which are newly installed in residentially zoned areas outside of mobile home parks, shall comply with the following requirements:

(1) Shall be newly constructed and shall not meet the definition of a used mobile home.

(2) Shall have a permanent perimeter foundation of either concrete, concrete masonry units or other approved concrete product.

(3) Shall meet the same design standard as the surrounding neighborhood for new construction.

(4) Shall be thermally equivalent to the State Energy Code.

(5) Shall be designed to support the local snow load of 25 pounds per square foot of ground snow load.

(6) Shall be designed to comply with the sound control requirements in this chapter. [Ord. 1407 § 41, 2007.]

14.08.170 Modular housing.

All modular homes, which are newly installed in residentially zoned areas outside of mobile home parks, shall comply with the following requirements:

(1) Shall be constructed in accordance with the International Residential Code. Factory-built homes are required to have a gold seal.

(2) Shall have a permanent perimeter foundation of either concrete, concrete masonry units or other approved concrete product.

(3) Shall meet the design standards of Title 18 DMMC for new construction.

(4) Shall meet the requirements of the State Energy Code.

(5) Shall be designed to support the local snow load of 25 pounds per square foot of ground snow load.

(6) Shall be designed to comply with the sound control requirements in this chapter. [Ord. 1407 § 42, 2007.]

ARTICLE I. SOUND CONTROL REQUIREMENTS

14.08.180 Purpose.

The purpose of this article is to safeguard life, health, property, and public welfare by establishing minimum requirements regulating the design, construction, and/or setting on site of buildings for human occupancy in the vicinity of Seattle-Tacoma International Airport. This article is not intended to abridge any safety or health requirements required under any other applicable codes or ordinances. [Ord. 1407 § 43, 2007.]

14.08.190 Provisions.

The provisions of this chapter shall apply to all buildings or structures, constructed or placed in use for human occupancy on sites within the vicinity of Seattle-Tacoma Airport, except:

(1) Additions under 500 square feet that are not used as sleeping rooms; and

(2) Remodels with a building department valuation less than $20,000 that do not include sleeping rooms.

New glazing in exempted additions and remodels shall conform to the provisions of this title. [Ord. 1407 § 44, 2007.]

14.08.200 Intent.

This article is intended to supplement the provisions of the International Mechanical Code, the Washington State Energy Code, the Washington State Ventilation and Indoor Air Quality Code, and the remainder of the International Building Code. In the case of conflict between this article and other applicable codes the more restrictive requirements, as determined by the building official, shall be met. [Ord. 1407 § 45, 2007.]

14.08.210 Application to existing buildings.

(1) Additions may be made to existing buildings or structures without making the entire building or structure comply with all the requirements of this chapter for new construction. Additions shall be made to comply in the areas being added to the extent that it is deemed practical and effective by the building official in meeting the intent of this article.

Exception: Substantial additions, alterations and remodels.

(2) A change in use in the occupancy or use previously unused for human occupancy to human occupancy use or of one previously unused for sleeping purposes to sleeping use shall not be permitted unless the building, structure, or portion of the building complies with this chapter.

Exception: Substantial additions, alterations and remodels. [Ord. 1407 § 46, 2007.]

14.08.220 Details.

The plans and specifications shall show in sufficient detail all pertinent data and features of the building and the equipment and systems, as herein governed, including, but not limited to: exterior envelope component materials; STC ratings of applicable component assemblies; R-values of applicable insulation materials; size and type of apparatus and equipment; equipment and system controls and other pertinent data to indicate conformance with the requirements herein. [Ord. 1407 § 47, 2007.]

14.08.230 Modifications and alterations.

Residential buildings’ modifications and alterations shall be in accordance with IRC Sections 104.10 and 104.11. Nonresidential buildings’ modifications and alterations shall be in accordance with IBC Sections 104.10 and 104.11. [Ord. 1407 § 48, 2007.]

14.08.240 Fees.

The building official is authorized to collect fees for administration, plan checking, and inspections. This fee shall be known as the airport noise fee and shall be as established by the city manager. [Ord. 1407 § 49, 2007.]

14.08.250 Design requirements.

The criteria of these sections establish the minimum requirements for acoustic design of the exterior envelope of buildings and for heating, ventilating, and air conditioning systems and its parts. These requirements shall apply to all buildings for human occupancy within the Seattle-Tacoma International Airport Noise Areas. [Ord. 1407 § 50, 2007.]

14.08.260 Seattle-Tacoma International Airport noise areas.

Noise determined construction requirements detailed in this sound transmission control building code shall be applied to new construction except for not normally inhabited portions of warehouses, storage buildings, and similar structures as determined by the building official, within the following areas:

Area 1 – Those portions of the city north of South 252nd Street or its extension.

Area 2 – Those portions of the city not included in Area 1. [Ord. 1407 § 51, 2007.]

14.08.270 Specific construction requirements for Areas 1 and 2.

(1) Area 1. All living and working areas must comply with this article, which is designed to achieve a noise reduction level of 35 dBA except: Owners of commercial occupancies classified as Group A or F may request the building official to reduce the noise reduction requirements to 30 dBA as provided in this article. Such request must be in writing and demonstrate, by approved methods, that the occupancy generates interior noise levels in excess of 70 dBA as a part of normal business.

(2) Area 2. All living and working areas must comply with this article, which is designed to achieve a noise reduction level of 30 dBA. [Ord. 1407 § 52, 2007.]

14.08.280 Air leakage for all buildings.

The requirements of this section shall apply to the design of the exterior envelope of all buildings in Areas 1 or 2 designed for human occupancy. The requirements of this section are not applicable to the separation of interior spaces from each other. The following locations shall be sealed, caulked, gasketed, or weather stripped to limit or eliminate air leakage:

(1) Exterior joints around window and door frames between the window or door frame and the framing.

(2) Openings between walls and foundations.

(3) Between the wall sole plate and the rough flooring.

(4) Openings at penetrations of utility services through walls, floor, and roofs.

(5) Between wall panels at corners.

(6) All other such openings in the building envelope.

(7) Through the wall, floor, or roof/ceiling penetrations not specifically addressed in these sections shall be designed to limit sound transmission and shall have the same average laboratory sound transmission classification as required for doors. [Ord. 1407 § 53, 2007.]

14.08.290 Compliance – Area 1.

Compliance with DMMC 14.08.300 through 14.08.360 shall be deemed to meet requirements for a minimum noise level reduction (NLR) of 35 decibels. [Ord. 1407 § 54, 2007.]

14.08.300 Exterior walls – Area 1.

(1) Exterior walls, other than as described in this section, shall have a laboratory sound transmission class rating of at least STC-40.

(2) Masonry walls having a weight of at least 75 pounds per square foot do not require a furred (stud) interior wall. At least one surface of concrete block walls shall be plastered.

(3) Stud walls shall be at least four inches in nominal depth and shall be finished on the outside with solid sheathing under an approved exterior wall finish.

(4) Interior surface of the exterior walls shall be of gypsum board or plaster at least five-eighths inch thick, installed on the studs. The gypsum board or plaster may be fastened rigidly to the studs if the exterior is brick veneer, stucco or one-quarter-inch cement fiber board siding. If the exterior is siding on sheathing, the interior gypsum board or plaster must be fastened resiliently to the studs or double thickness must be used.

(5) Continuous composition board, plywood or gypsum board sheathing at least one inch thick shall cover the exterior side of the wall studs.

(6) Sheathing panels shall be butted tightly and covered on the exterior with overlapping building paper.

(7) Insulation material of a type approved by the building official and rated not less than R-21 or the current energy code requirement, whichever is the greater, shall be installed continuously throughout the cavity space behind the exterior sheathing and between wall studs. [Ord. 1407 § 55, 2007.]

14.08.310 Exterior windows – Area 1.

(1) Windows other than as described in this section shall have a laboratory sound transmission class rating of at least STC-38.

(2) Windows shall be double glazed with panes at least three-sixteenths inch thick. Panes of glass shall be separated by a minimum one-half-inch airspace and shall not be equal in thickness.

(3) Double-glazed windows shall employ fixed sash or efficiently weatherstripped, operable sash. The sash shall be rigid and weatherstripped with material that is compressed airtight when the window is closed so as to conform to an air infiltration test not to exceed one-half cubic foot per minute per foot of crack length in accordance with ASTM E-283-65-T.

(4) Glass shall be sealed in an air-tight manner with a nonhardening sealant or a soft elastomer gasket or gasket tape.

(5) The perimeter of window frames shall be sealed airtight to the exterior wall construction with a sealant conforming to one of the following federal specifications: TT-S-00227, TT-S-00230, or TT-S-00153, or other materials approved by the building official. [Ord. 1407 § 56, 2007.]

14.08.320 Exterior doors – Area 1.

(1) Doors other than as described in this section shall have a laboratory sound transmission class rating of at least STC-33.

(2) Double door construction is required for all hinged-door openings to the exterior. Such doors shall be side-hinged and shall be solid core wood or insulated hollow metal at least one and three-fourths inch thick separated by an airspace of at least three inches from another door. Both doors shall be tightly fitted and weather stripped.

(4) Glass of all doors shall be at least three-sixteenths inch thick. Glass of double sliding doors shall not be equal in thickness.

(5) The perimeter of door frames shall be sealed airtight to the exterior wall construction with a sealant conforming to one of the following federal specifications: TT-S-00227, TT-S-00230, or TT-S-00153, or other materials approved by the building official.

(6) Glass in doors shall be sealed in an airtight nonhardening sealant or in a soft elastomer gasket or glazing tape. [Ord. 1407 § 57, 2007.]

14.08.330 Roofs – Area 1.

(1) Combined roof and ceiling construction other than described in this section and DMMC 14.08.340 shall have a laboratory sound transmission class rating of at least STC-49.

(2) With an attic or rafter space at least six inches deep, and with a ceiling below, the roof shall consist of one inch composition boards, plywood, or gypsum board sheathing topped by roofing as required.

(3) Open beam roof construction shall follow the energy insulation standard method for batt insulation, except use one inch plywood decking with concrete or clay tiles as roofing material.

(4) Window or dome skylights shall have a laboratory sound transmission class rating of at least STC-38. [Ord. 1407 § 58, 2007.]

14.08.340 Ceilings – Area 1.

(1) Gypsum board or plaster ceilings at least five-eighths inch thick shall be provided where required by DMMC 14.08.330. Ceilings shall be substantially airtight with a minimum of penetrations. The ceiling panels shall be mounted on resilient clips or channels.

(2) Insulation material of a type approved by the building official and rated not less than R-38 or the current energy code requirement, whichever is the greater, shall be provided above the ceiling between joists. [Ord. 1407 § 59, 2007.]

14.08.350 Floors – Area 1.

The floor of the lowest occupied rooms shall be slab on fill or below grade, or over a fully enclosed basement or crawl space. All door and window openings in a fully enclosed basement shall be tightly fitted. [Ord. 1407 § 60, 2007.]

14.08.360 Ventilation – Area 1.

(1) A ventilation system shall be installed that will provide the minimum air circulation and fresh air supply requirements for various uses in occupied rooms without the need to open any windows, doors or other openings to the exterior. The inlet and discharge openings shall be fitted with sheet metal transfer ducts of at least 20 gauge steel, which shall be lined with one-inch-thick coated glass fiber, and shall be at least five feet long with one 90-degree bend.

(2) Gravity vent openings in attics shall be as close to code minimum, in number and size, as practical. The openings shall be fitted with transfer ducts at least six feet in length containing internal one-inch-thick coated fiberglass sound-absorbing duct lining. Each duct shall have a lined 90-degree bend in the duct such that there is no direct line of sight from the exterior through the duct into the attic or be adequately baffled to dissipate any direct sound transfer from the exterior environment.

(3) Source-specific exhaust shall be at least 70 cfm at the outlet.

(4) Bathroom, laundry and similar exhaust ducts connecting the interior space to the outdoors shall be provided with a 90-degree bend in the duct such that there is no direct line of sight through the duct from the venting cross-section to the room-opening cross-section. Duct lining shall be coated glass fiber duct liner at least one inch thick or approved flexible duct material.

(5) Domestic range exhaust ducts connecting the interior space to the outdoors shall contain a self-closing damper across the exterior termination which allows proper ventilation. [Ord. 1407 § 61, 2007.]

14.08.370 Compliance – Area 2.

Compliance with DMMC 14.08.380 through 14.08.440 shall be deemed to meet requirements for a minimum noise level reduction (NLR) of 30 decibels. [Ord. 1407 § 62, 2007.]

14.08.380 Exterior walls – Area 2.

(1) Exterior walls, other than as described in this section, shall have a laboratory sound transmission class rating of at least STC-35.

(2) Masonry walls having a weight of at least 40 pounds per square foot do not require a furred (stud) interior wall. At least one surface of concrete block walls shall be plastered.

(3) Stud walls shall be at least four inches in nominal depth and shall be finished on the outside with solid sheathing under an approved exterior wall finish.

(4) Interior surface of the exterior walls shall be of gypsum board or plaster at least one-half inch thick, installed on the studs. The gypsum board or plaster may be fastened rigidly to the studs if the exterior is brick veneer or stucco. If the exterior is siding on sheathing, the interior gypsum board or plaster must be fastened resiliently to the studs or double thickness must be used.

(5) Continuous composition board, plywood or gypsum board sheathing at least three-fourths inch thick shall cover the exterior side of the wall studs.

(6) Sheathing panels shall be covered on the exterior with overlapping building paper.

Insulation material of a type approved by the building official and rated not less than R-21 or the current energy code requirement, whichever is the greater, shall be installed continuously throughout the cavity space behind the exterior sheathing and between wall studs. [Ord. 1407 § 63, 2007.]

14.08.390 Exterior windows – Area 2.

(1) Windows other than as described in this section shall have a laboratory sound transmission class rating of at least STC-33.

(2) Windows shall be double glazed with panes at least one-eighth inch thick.

(3) Panes of glass shall be separated by a minimum one-half inch airspace.

(4) Double-glazed windows shall employ fixed sash or efficiently weather stripped, operable sash. The sash shall be rigid and weather stripped with material that is compressed airtight when the window is closed so as to conform to an air infiltration test not to exceed one-half cubic foot per minute per foot of crack length in accordance with ASTM E-283-65-T.

(5) Glass shall be sealed in an airtight manner with a nonhardening sealant or a soft elastomer gasket or gasket tape.

(6) The perimeter of window frames shall be sealed airtight to the exterior wall construction with a sealant conforming to one of the following federal specifications: TT-S-00227, TT-S-00230, or TT-S-00153, or other materials approved by the building official. [Ord. 1407 § 64, 2007.]

14.08.400 Exterior doors – Area 2.

(1) Doors other than as described in this section shall have a laboratory sound transmission class rating of at least STC-33.

(2) Double door construction is required for all hinged-door openings to the exterior. Such doors shall be side-hinged and shall be solid core wood or insulated hollow metal at least one and three-fourths inch thick separated by an airspace of at least three inches from another door, which can be a storm door. Both doors shall be tightly fitted and weather stripped.

(3) The glass of double-glazed sliding doors shall be separated by a minimum one-half-inch airspace. Each sliding frame shall be provided with an efficiently airtight weather stripping material to the exterior wall construction with a sealant conforming to one of the following federal specifications: TT-S-00227, TT-S-00230, or TT-S-00153, or other materials approved by the building official.

(4) Glass, over two square feet in area, of all doors shall be at least three-sixteenths inch thick. Glass of double sliding doors shall not be equal in thickness.

The perimeter of door frames shall be sealed airtight to the exterior wall construction with a sealant conforming to one of the following federal specifications: TT-S-00227, TT-S-00230, or TT-S-00153, or other materials approved by the building official.

(5) Glass in doors shall be sealed in an airtight nonhardening sealant or in a soft elastomer gasket or glazing tape. [Ord. 1407 § 65, 2007.]

14.08.410 Roofs – Area 2.

(1) Combined roof and ceiling construction other than described in this section and DMMC 14.08.420 shall have a laboratory sound transmission class rating of at least STC-44.

(2) With an attic or rafter space at least six inches deep, and with a ceiling below, the roof shall consist of three-fourths-inch composition boards, plywood, or gypsum board sheathing topped by roofing as required.

(3) Open beam roof construction shall follow the energy insulation standard method for batt insulation, except use one-inch plywood decking with shakes or other suitable roofing material.

(4) Window or dome skylights shall have a laboratory sound transmission class rating of at least STC-33. [Ord. 1407 § 66, 2007.]

14.08.420 Ceilings – Area 2.

(1) Gypsum board or plaster ceilings at least five-eighths-inch-thick shall be provided where required by DMMC 14.08.410. Ceilings shall be substantially airtight with a minimum of penetrations.

14.08.430 Floors – Area 2.

14.08.440 Ventilation – Area 2.

(2) Gravity vent openings in attics shall be as close to code minimum in number and size as practical. The openings shall be fitted with transfer ducts at least three feet in length containing internal one-inch-thick coated fiberglass sound-absorbing duct lining. Each duct shall have a lined 90-degree bend in the duct such that there is no direct line of sight from the exterior through the duct into the attic or be adequately baffled to dissipate any direct sound transfer from the exterior environment.

(3) Bathroom, laundry and similar exhaust ducts connecting the interior space to the outdoors shall be provided with a 90-degree bend in the duct such that there is no direct line of sight through the duct from the venting cross-section to the room-opening cross-section. Duct lining shall be coated glass fiber duct liner at least one inch thick and be at least a 70 cfm rated fan at the outlet.

(4) Domestic range exhaust ducts connecting the interior space to the outdoors shall contain a self-closing damper across the exterior termination which allows proper ventilation. [Ord. 1407 § 69, 2007.]