§ 403.21. Uniform Construction Code.

 (a)  The Department adopts and incorporates by reference the following codes as the Uniform Construction Code:

   (1)  The provisions of Chapters 2—10, 12—29 and 31—35 of the ‘‘International Building Code,’’ except that in occupancies in Use Group R-3 and within dwelling units in occupancies in Use Group R-2 the maximum riser height shall be 8 1/4 inches (210 mm) and the minimum tread depth shall be 9 inches (229 mm). A 1-inch (25 mm) nosing shall be provided on stairways with solid risers.

   (2)  Chapter 11 of the ‘‘International Building Code of 2012.’’

   (3)  The ‘‘International Mechanical Code.’’

   (4)  The ‘‘International Fuel Gas Code.’’

   (5)  The ‘‘International Performance Code.’’

   (6)  The ‘‘International Plumbing Code.’’

     (i)   Except that a municipality within a county of the second class may not administer and enforce the ‘‘International Plumbing Code’’ adopted under this chapter.

     (ii)   A municipality within a county of the second class that has adopted a plumbing code and accompanying rules and regulations under the Local Health Administration Law (16 P. S. § §  12001—12028), shall retain the authority to promulgate and enforce this plumbing code and to make any changes it deems necessary if the changes meet the Uniform Construction Code’s minimum requirements.

   (7)  The ‘‘International Residential Code,’’ except that:

     (i)   The provisions of R314.4 requiring interconnected smoke alarms do not apply to one-family and two-family dwellings undergoing alterations, repairs or additions. Noninterconnected battery operated smoke alarms shall be installed in these dwellings.

     (ii)   The following specifications apply to residential stairway treads and risers.

       (A)   The maximum riser height is 8 1/4 inches. There may be no more than a 3/8 inch variation in riser height within a flight of stairs. The riser height is to be measured vertically between leading edges of the adjacent treads.

       (B)   The minimum tread depth is 9 inches measured from tread nosing to tread nosing.

       (C)   The greatest tread depth within any flight of stairs may not exceed the smallest by more than 3/8 inch.

       (D)   Treads may have a uniform projection of not more than 1 1/2 inches when solid risers are used.

       (E)   Stairways may not be less than 3 feet in clear width and clear headroom of 6 feet 8 inches shall be maintained for the entire run of the stair.

       (F)   Handrails may project from each side of a stairway a distance of 3 1/2 inches into the required width of the stair.

   (8)  The ‘‘International Fire Code.’’ Section 806.1.1 of the International Fire Code (relating to natural cut trees) is not adopted under this chapter. A municipality that elects to adopt an ordinance for the administration and enforcement of the Uniform Construction Code may, by ordinance, restrict the placement of natural cut trees in an occupancy group. The ordinance restricting the placement of natural cut trees is not subject to section 503(b)—(k) of the act (35 P. S. §  7210.503(b)—(k)) and §  403.102(i)—(k) (relating to municipalities electing to enforce the Uniform Construction Code).

   (9)  The ‘‘International Energy Conservation Code.’’

   (10)  The ‘‘International Existing Building Code.’’

   (11)  The ‘‘International Wildland-Urban Interface Code.’’

   (12)  Appendix E of the ‘‘International Building Code of 2012.’’

   (13)  Appendix H of the ‘‘International Building Code.’’

   (14)  Appendix G of the ‘‘International Residential Code.’’

 (b)  The code adopted under subsection (a)(7) is part of the Uniform Construction Code to the extent that it is referenced in Chapter 35 of the ‘‘International Building Code’’ under section 302(a)(1) of the act (35 P. S. §  7210.302(a)(1)). The provisions of the Uniform Construction Code apply if there is a difference between the Uniform Construction Code and the codes or standards adopted in subsection (a). This chapter’s administrative provisions govern under §  403.27(e) (relating to applicability and use of standards) if there is a conflict with the provisions of the codes relating to administration incorporated under subsection (a).

 (c)  Appendices to a code or standard listed in subsection (a) are not adopted in the Uniform Construction Code except for the appendices and resource information found in the ‘‘International Existing Building Code’’ and the appendices found in (a)(11)—(13).

 (d)  A permit applicant may utilize one of the following prescriptive methods to demonstrate compliance with the energy conservation requirements of the Uniform Construction Code. The standards are those listed for the climatic zone of this Commonwealth where the building or structure is located:

   (1)  The prescriptive methods for detached residential buildings contained in the current version of the ‘‘International Energy Conservation Code’’ compliance guide containing State maps, prescriptive energy packages and related software published by the United States Department of Energy, Building Standards and Guidelines Program (REScheck_TM) or ‘‘Pennsylvania’s Alternative Residential Energy Provisions.’’

   (2)  The prescriptive methods for all other buildings or structures contained in the current version of the ‘‘International Energy Conservation Code’’ compliance guide containing State maps, prescriptive packages and related software published by the United States Department of Energy, Building Standards and Guidelines Program (COMcheck_TM).

 (e)  Construction of individual sewage disposal systems is governed under 25 Pa. Code Chapter 73 (relating to onlot sewage treatment facilities).

 (f)  The repair, alteration, change of occupancy, addition and relocation of existing buildings must comply with Chapter 34 of the ‘‘International Building Code’’ or with the ‘‘International Existing Building Code.’’

   The provisions of this §  403.21 amended under section 304(a)(3) of the Pennsylvania Construction Code Act (35 P. S. §  7210.304(a)(3)).

   The provisions of this §  403.21 amended December 15, 2006, effective December 31, 2006, 36 Pa.B. 7548; amended December 24, 2009, effective December 31, 2009, 39 Pa.B. 7196; amended December 21, 2012, effective December 31, 2012, 42 Pa.B. 7646. Immediately preceding text appears at serial pages (347290) to (347293).

   The Department of Labor and Industry had the authority to adopt model codes to serve as basis for the Uniform Construction Code; this authority included the implied authority to incorporate an appendix of the International Residential Code setting standards for manufactured homes which the Department deemed relevant. DRB v. Department of Labor, 853 A.2d 8, 18, 19 (Pa. Cmwlth. 2004) aff’d 887 A.2d 1216 (Pa. 2005).

   This section cited in 34 Pa. Code §  403.2 (relating to other statutes or ordinances); 34 Pa. Code §  403.27 (relating to applicability and use of standards); 34 Pa. Code §  403.44 (relating to alternative construction materials and methods); and 34 Pa. Code §  403.102 (relating to municipalities electing to enforce the Uniform Construction Code).