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Inspecting CSST – Corrugated Stainless Steel Tubing

Corrugated Stainless Steel Tubing or CSST is not a new product. It has been used in the US for more than 20 years and there are more than 750 million feet installed since then. It is not the flexible stainless steel pipe used for ranges or clothes dryers. It should not be directly connected to these appliances. It can be connected to black iron pipe. CSST can be identified by its yellow or black exterior jacket and corrugated look. CSST has been approved for gas service by the Uniform Plumbing Code, International Fuel Gas Code, and all 50 States. CSST should be installed by a qualified trained installer. All holes bored in structural members should be in accordance with local building requirements. When inspecting CSST; we should look for the following:

  • If installed through masonry, it must be routed in conduit that is ½ inch larger than the OD of the CSST. The conduit must maintain a continuous watertight barrier between the masonry and CSST.
  • CSST must be bonded to the electric service grounding with at least a number 6 AWG copper wire or equivalent.
  • Concealed CSST should be protected from puncture using striker plates at all points of penetration through studs, joists, etc.
  • All points of penetration less than 2 inches from any edge of a stud, joist, plate, etc. should be protected by a striker plate to provide protection at the area of support and within 5 inches of each side of the support.
  • A striker plate should be installed at points of penetration 2-3 inches from any edge of a stud, joist, or plate.
  • Points of penetration greater than 3 inches from the edge of a stud or joist do not require protection.
  • CSST traveling horizontally through studs shall be protected from puncture between the studs using shielding devices
  • The width of protection striker plates at the penetration points through wall studs, floor joists, sills, etc., should be at least 1.5 times the outside diameter of the tubing.
  • Open ends of CSST should be plugged or taped closed during installation to prevent dirt or debris to enter.
  • The protective yellow jacket should be kept in place as much as possible to protect the tubing from corrosive threats.
  • Installation clearance holes for routing CSST are to be ½ inch greater than the O.D. of the CSST.
  • CSST should be supported with pipe straps, bands, or hangers every 4’ for 3/8”, 6’ for ½”, 8’ for ¾”.
  • CSST should be installed without any sharp bends, kinks, stretching, kinking, or twisting.
  • CSST should not be connected to any moveable appliances
  • CSST should not be buried or embedded in the ground or concrete, or installed along the outside a structure unless it is routed inside a non-metallic watertight conduit that has an outside diameter at least ½” greater than the O.D. of the CSST. The conduit should be properly sealed to prevent water from entering.
  • CSST should not be used to support a gas meter
  • Where a hole is bored in a joist, the hole should be in the centerline, otherwise no closer than 2” from the nearest edge of the joist.
  • When CSST passes through metal members it must be protected by grommets, bushings, armor, PVC tape, shrink sleeve material, or a minimum of four wraps of #10 Mil duct tape to ensure there is no physical damage to the CSST.
  • CSST should not be installed in notches cut in either the top or bottom of joists

Smoke and Carbon Monoxide detectors should be installed in every home. Most home inspectors (and many municipalities) recommend smoke detectors on every level of the living space, in all hallways, common areas and every bedroom.

Carbon monoxide detectors should be on every level of the house. Some municipalities do not allow plug in type Carbon Monoxide detectors. Electric interconnected with battery back-up dual units are a great choice for your clients.

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