Thread seal tape

Thread seal tape (also known as PTFE tape or plumber’s tape) is a polytetrafluoroethylene (PTFE) film for use in sealing pipe threads. The tape is sold cut to specific widths and wound on a spool, making it easy to wind around pipe threads. It is also known by the genericised trade-name Teflon tape; while Teflon is in fact identical to PTFE, Chemours (the trade-mark holders) consider this usage incorrect, especially as they no longer manufacture Teflon in tape form.Thread seal tape lubricates allowing for a deeper seating of the threads, and it helps prevent the threads from seizing when being unscrewed.The tape also works as a deformable filler and thread lubricant, helping to seal the joint without hardening or making it more difficult to tighten,and instead making it easier to tighten.

Typically the tape is wrapped around a pipe’s thread three times before it is screwed into place. It is commonly used commercially in applications including pressurized water systems, central heating systems, and air compression equipment.

Types

Thread seal tape is usually sold in small spools.
There are two US standards for determining the quality of any PTFE tape. MIL-T-27730A (an obsolete military specification still commonly used in industry in the US) requires a minimum thickness of 3.5 mils and a minimum PTFE purity of 99%.The second standard, A-A-58092,is a commercial grade which maintains the thickness requirement of MIL-T-27730A and adds a minimum density of 1.2 g/cm3.Relevant standards may vary between industries; tape for gas fittings (to UK gas regulations) is required to be thicker than that for water. Although PTFE itself is suitable for use with high-pressure oxygen, the grade of tape must also be known to be free from grease.

Thread seal tape used in plumbing applications is most commonly white, but it is also available in various colors. It is often used to correspond to color coded pipelines (US, Canada, Australia and New Zealand: yellow for natural gas, green for oxygen, etc.). These color-codes for thread sealing tape were introduced by Bill Bentley of Unasco Pty Ltd in the 1970s. In the UK, tape is used from coloured reels, e.g. yellow reels for gas, green for potable water.

White – used on NPT threads up to 3/8 inch
Yellow – used on NPT threads 1/2 inch to 2 inch, often labeled “gas tape”
Pink – used on NPT threads 1/2 inch to 2 inch, safe for propane and other hydrocarbon fuels
Green – oil-free PTFE used on oxygen lines and some specific medical gasses
Gray – contains nickel, anti-seizing, anti-gailling and anti-corrosion, used for stainless pipes
Copper – contains copper granules and is certified as a thread lubricant but not a sealer
In Europe the BSI standard BS-7786:2006 specifies various grades and quality standards of PTFE thread sealing tape.