Using Teflon Tape to Seal Threaded Joints on Gas Lines

Using Teflon Tape on Gas Lines

Teflon tape, also known as PTFE tape, is commonly used to seal threaded pipe joints in plumbing applications. It is an important component when installing gas lines in order to prevent leaks. Using the proper techniques when applying Teflon tape on gas pipes is crucial for safety.

What is Teflon Tape?

Teflon tape, sometimes referred to as thread seal tape, is a thin, consumable tape made from PTFE (polytetrafluoroethylene). It is non-adhesive, stretchy, resistant to oils and chemicals, and can withstand high temperatures. These properties make it the ideal sealing material for wrapping around threaded joints in pipes.

The tape is stretched slightly as it is wrapped around pipe threads. This stretching causes it to conform to the threads, filling in any small gaps or abrasions in the threads. The Teflon tape helps create a tighter seal and prevent leaks from the threaded joint.

Why Use Teflon Tape on Gas Lines?

Using Teflon tape on gas line connections is highly recommended for several reasons:

• Creates a gas-tight seal - The tape fills in gaps in the threads and prevents gas leaks.
• Compensates for slightly imperfect threads - Irregular or damaged threads can be sealed with Teflon tape.
• Makes joints easy to disassemble - The non-permanent seal allows joints to be unscrewed if needed.
• Withstands gas pressure - The tape holds up to the high pressures found in gas line systems.
• Resists temperatures - Teflon holds up well to temperature extremes often seen in gas appliances.
• Non-reactive - Teflon won't react with natural gas or propane gases.

For these reasons, plumbing codes require the use of Teflon tape on threaded joints in gas piping systems. This helps ensure a leak-free connection.

Teflon Tape Grades and Specifications

Teflon tape is available in different grades and specifications:

• Standard grade - This thin tape is good for low pressure sealing. It conforms well to threads.
• Heavy duty grade - A thicker tape that provides extra protection for high pressure systems.
• Pipe size - Tapes come in different widths for different pipe diameters. 1/2" and 3/4" are common sizes.
• Density - Higher density tapes tend to be better quality. Look for tapes rated at 2.5+ grams per cubic centimeter.
• Approvals - Tapes approved for gas service will be printed on the package. Look for UL, CSA, NSF seals.

Plumbers generally recommend using high density, heavy duty gas service grade Teflon tape. This provides the best seal and durability for gas lines.

How to Apply Teflon Tape on Gas Pipes

Applying Teflon tape properly is crucial for creating a leak-free seal:

1. Clean threads - Use a wire brush to remove any dirt, grease or old tape from the threads.
2. Wrap in direction of thread - Wrapping the tape in the same direction as the pipe threads allows it to conform better to the threads when screwed in.
3. Stretch slightly - Pull gently on the tape while wrapping to make it confirm tightly to the threads.
4. 2-3 wraps - Multiple wraps creates a thicker seal. 3 wraps is commonly recommended.
5. Cover full thread - Start below the threads and wrap up till just before the end.
6. No overlap - Don't let the tape overlap itself. This can cause bunching.
7. Leave end exposed - Leave the first couple threads exposed so the tape doesn't come loose.
8. Screw joint tightly - Tightening compresses the tape into the joint.

Following these proper taping techniques helps prevent leaks, blocks corrosion, and allows for easier future disassembly if needed.

Common Teflon Taping Mistakes

It's important to avoid these common mistakes when using Teflon tape:

• Too little tape - The more wraps the better to fill voids.
• Too much tape - Excess tape can bunch up and inhibit proper tightening.
• Tape applied backwards - Wrapping against the thread direction can allow leaks.
• Overlapping tape - Letting the tape overlap can cause bunching.
• Covering first threads - Keeping first threads clear prevents loose tape.
• Not fully tightening - After taping, joints need full tightening to seal.

Being aware of these mistakes allows you to properly apply the tape and achieve a secure, leak-free connection.

Using Teflon Tape on Brass or Plastic Fittings

Teflon tape can be used on brass, plastic, or other pipe materials. The non-stick tape provides a universal threaded sealant. Some tips for using Teflon tape with various fittings:

• Brass - Brass is prone to seizing up, so use moderate tightening force.
• PVC/ABS plastic - Only hand tighten plastic fittings to avoid cracking. Tighten 1/4 turn past hand tight.
• Plastic to metal connections - Tighten plastic connections to metal very gently to prevent stripped threads.

Adjust your tightening force appropriately when using Teflon tape on plastic or brass fittings. Over-tightening can cause damage. The tape still provides an effective seal at lower tightness.

Is Teflon Tape Gas Approved?

Standard Teflon tape is approved for use on gas lines. Look for tapes that meet these certifications:

• UL - UL813 certification for gas service
• CSA - Canadian Standards Association approval for fuel gases
• NSF - Meets standards for low pressure gas systems

Tapes meeting these standards are safe for use on natural gas, propane, and LPG systems. The packaging will be printed with the certification seals if approved for gas service.

Alternatives to Teflon Tape

While Teflon tape is the top choice of plumbers for gas connections, there are some alternatives including:

• Pipe dope/thread sealant - Pipe dope can be used alone or with tape. It seals less effectively than tape alone.
• Metal crush washers - Copper or aluminum washers can be used to make flare fittings leak proof.
• UL-approved gas pipe compound - Special hardening compounds can seal threads long-term.

However, Teflon tape is inexpensive, easy to use, and provides the best seal for gas connections. That's why it remains the go-to thread sealant for gas line installations and repairs.

Key Takeaways on Teflon Tape for Gas Lines

Here are some key tips to remember about using Teflon tape on gas pipes:

• Wrap pipe threads with 2-3 layers of Teflon tape to prevent leaks.
• Tape must be applied correctly in the thread direction with proper tightening.
• Use only thick, heavy duty UL/CSA approved gas service Teflon tapes.
• Avoid common mistakes like too little tape, sloppy wrapping, or over-tightening.
• Teflon tape can be used on brass, plastic, or metal gas fittings.
• Tape provides a superior gas seal versus pipe dope or other alternatives.

Using quality Teflon tape properly is simple and inexpensive insurance against dangerous gas leaks. Following proper taping procedures and certifications ensures safe, durable, and leak-free gas connections.

FAQs

How many wraps of Teflon tape should be used on gas fittings?

2-3 wraps of Teflon tape is recommended for gas pipes. Multiple wraps helps fill in voids in the threads to prevent leaks.

Can you use too much Teflon tape on pipes?

Yes, using excessive Teflon tape can cause problems. Too much tape can bunch up and prevent proper tightening of the joint. 3 wraps is typically sufficient.

What direction should you wrap Teflon tape?

Wrap the Teflon tape in the same direction the pipe threads run. This enables the tape to stick into the grooves better when tightened.

Can you use Teflon tape on plastic threaded fittings?

Yes, Teflon tape can be used to seal plastic fittings but extra care needs to be taken not to over-tighten and crack the plastic.

Is pipe dope or paste better than Teflon tape?

No, Teflon tape typically provides a better gas seal than pipe dope alone. Pipe dope is sometimes used together with Teflon tape for additional sealing capability.