In general, pipe tape is not necessary for flared connections. Flare fittings are a common type of plumbing connection for gas ranges and other applications where appropriate. Pipe thread sealant or Teflon tape is used to seal threads on pipe connections to prevent leaks of water or gas. In this article, we explain why flare connections do not need pipe thread sealant.
How Flare Fittings Create Leak-Tight Seals
Flare fittings create leak-tight seals by the metal-to-meal connection of the flared pipe and threaded connection of the male fitting and the female threaded nut.
The sealant of the flare connection is due to the flared face of the pipe mating with the flared face of the fitting and secured together by the threaded nut.
When Should Pipe Sealant Tape Be Used?
Pipe sealant tape should be use on threaded fittings with male iron pipe (MIP) or NPT threads. For gas line or fuel lines, NPT threaded pipe such as steel, Teflon tape or pipe dope should be used to seal the threaded joints.
For flare fittings with NPT threaded ends such as flexible gas connector hoses, the male NPT threads should have pipe sealant tape applied to them prior to installing the fitting.
Should I Use Pipe Sealant Tape or Pipe Joint Compound?
Pipe sealant tape and pipe joint sealant both work by closing the gaps between the thread peaks and roots. Pipe sealant tape and pipe joint compound both contain polytetraflouroethylene or PTFE which is a polymer that has numerous properties but works by preventing water absorption and is hight-temperature resistant. Pipe sealant tape is commonly Teflon tape and pipe joint compound is commonly called pipe dope.
Tape or sealant will provide the same result but each has their advantages. Teflon tape is less expensive, creates less mess, and can be wrapped multiple times to create a thicker seal. Pipe sealant is easier to use and can be used on male and female threaded fittings. Some plumbers use both sealant and tape to provide both but for most applications, only one type of sealant is used.
Can I Use Pioneer® Flare Connection Leak Sealer?
Pioneer® Flare Connection Leak Sealer is a product for use on copper flare fittings in air conditioning or refrigeration systems. It is recommended for use only with R-410a refrigerant and should not be used with copper flare fittings in other applications.
Can I use NYLOG BLUE® or NYLOG RED® Gasket and Thread Sealant?
NYLOG BLUE® and NYLOG RED®are products for use on flare fittings in air condition or refrigeration systems. Like Pioneer Flare Connection Leak Sealer, it is not be used on fuel flare fittings such as natural gas or liquid propane.
NYLOG WHITE is a pipe joint compound that can be used on threaded connections similar to other thread sealant tapes or joint compounds that contain PTFE.
What Should You Do If You Use Pipe Thread Tape on Flare Fittings?
If you apply pipe thread tape on flare fittings there is a risk of an improper seal due to the tape or joint compound interfering with flange sealing. If you applied pipe thread tape or pipe joint compound to flare fitting, remove the tape and compound and thoroughly clean the fitting.
Pipe joint compound that enters the hose or connector can contaminate the gas line. If joint compound enters fuel lines or gas lines, it can cause a blockage that may create blockages that can lead to poor performance of appliances or dangerous build up.
How Do You Test Flare Fittings for Leaks?
Flare fittings are tested for leaks in the same way other pipe is tested for leaks. For gas lines, soapy water or a liquid leak detection solution can be used to test gas connectors to check for leaks. If bubbles appear around the joints, there is a gas leak.
Another way to test is by using an electronic gas detector. Detectors range in price and use but for most home owners, an electronic gas detector that can detect natural gas and propane gas will be useful for home appliances such as ranges and dryers.
Conclusion
Pipe thread tape is not necessary for sealing flare fittings. Flare fitting are sealed by flanged metal-to-metal contact that prevents liquid or gas from escaping the sides of fitting, especially under high pressure. Pipe thread tape or pipe joint compound is necessary for flare fittings that have standard pipe threads.