1217.8 Poured Floor Structural Concrete Slab Sys-

tems (Thermal Mass). Where tubing is embedded in a structural concrete slab such tubes shall not be larger in outside dimension than one-third of the overall thickness of the slab and shall be spaced not less than three diameters on center except within 10 feet (3048 mm) of the distribution manifold. The top of the tubing shall be embedded in the slab not less than 2 inches (51 mm) below the surface.

1217.8.1 Slab Penetration Tube and Joint Protec- tion. Where embedded in or installed under a concrete slab, tubing shall be protected from damage at penetrations of the slab with protective sleeving recommended by the tubing manufacturer. The space between the tubing and sleeve shall be sealed with an approved sealant compatible with the tubing. The tubing at the location of an expansion joint in a concrete slab shall be encased in protective pipe sleeving that covers the tubing not less than 12 inches (305 mm) on either side of the expansion joint or the tubing shall be installed below the slab. 1217.8.2 Insulation. Where a poured concrete radiant floor system is installed in contact with the soil, insulation recommended by the manufacturer for such application and with a minimum R-value of 5 shall be placed between the soil and the concrete; extend to the outside edges of the concrete; and be placed on all slab edges. 1217.8.2.1 California Energy Code Insulation Requirements for Heated Slab Floors. See California Energy Code Section 110.8(g) for addi- tional insulation requirements for heated slab floors – a higher level of insulation is required for Climate Zone 16, and more detailed installation require- ments apply to all climate zones. 1217.8.3 Types of Tube Fasteners. Tubing that is embedded within concrete shall be fastened according to manufacturer’s instructions. Unless prohibited by the manufacturer, tube fasteners include the following:

(1) Ties made of wire, typically fastened to anchors such as rebar or wire mesh.

(2) Plastic tube/cable ties, typically nylon, fastened to anchors such as rebar or wire mesh.

(3) Staples made of metal or plastic or combination thereof, without sharp edges that would harm tube, fastened to insulation or subfloor.

(4) Plastic rails with integrated tube holders intended for the specific type of tube.

(5) Insulation sheets with integrated knobs for holding the specific type of tube and intended for this application.

(6) Other fasteners recommended by the manufacturer. 1217.8.4 Spacing of Tube Fasteners. The maximum spacing between tube fasteners within a concrete floor shall not exceed the spacing specified by the manufacturer or, in the absence of manufacturer’s specifications, 2.5 feet (762 mm).