Disclaimer: These tips are not a replacement for proper training. Please also ensure that all work is performed in accordance with any applicable laws and regulations in your area.
Gas torches are often used in commercial low slope roofing to apply modified bitumen membranes. It is important to understand a roofing torch’s components, including its regulator, to operate it safely. Further, you also need to understand propane and other liquid petroleum (LP) fuels. This article will introduce you to all of these essentials.
Parts of the Gas Torch and Tank
Gas torches used for roofing need to be Underwriters Laboratory (UL) approved. Approved torches may have different specifications, so always read through the manual provided by the manufacturer. However, the basics of the gas torch and tank are as follows:
The LP Cylinder consists of the parts listed below:
Propane Regulators for Roofing Applications
The regulator is perhaps the most essential part of the roofing torch system. It controls the PSI and the British Thermal Units (BTU) of the torch. Roofing torches generally require between 30 and 60 psi and need up to 300,000 BTU. This calls for a high-pressure regulator, which is usually painted red.
Some mistakenly believe that any red regulator can be swapped out for another, but this is not the case. Some blow torch gas regulators are installed at the tank, and others are installed in the line. Plus, there are different high-pressure regulators for liquid and vapor withdrawal systems and different regulators for one-stage or two-stage systems. You should always use a regulator supplied by your torch manufacturer.
It’s helpful for the roofing professional to understand the difference between one-stage and two-stage regulators. In a one-stage system, the regulator delivers the fuel from the tank right into the hose at the right pressure.
In contrast, two-stage regulators actually combine two different regulators. The first regulator in this system delivers your fuel from the tank into the hose but at a low pressure. The second regulator provides more pressure, which allows the torch to achieve more BTU over longer hose distances.
A roofing professional will likely use a two-stage regulator because a high amount of BTU and a long hose are both required for most roofing applications. Sometimes these two regulators can be combined into one component, which is called an integral twin regulator. However, these regulators can’t provide as much pressure as two-stage regulators.
A roofing torch requires an adjustable high-pressure regulator, as opposed to a non-adjustable regulator. This doesn’t mean that you can manually change the propane torch regulator settings. Instead, it means that the regulator will automatically adjust as you squeeze the torch’s lever, allowing for more or less pressure. You should not attempt to change the propane torch regulator settings yourself. Have a qualified professional do so.
You may find that you need one general-purpose roofing torch and another for finer detail work, which requires much less BTU. A typical detail propane torch would achieve less than 105,000 BTU, a far cry from the average maximum of full-sized torches at 300,000 BTU. Instead of trying to adjust your propane torch’s regulator settings to achieve the lower output, it’s better to have two torches, one dedicated to smaller detail work.
Most roofers will examine their torch’s performance based on how the roofing membrane reacts instead of using an exact temperature for their work. A properly heated membrane will shine. Some manufacturers place a film on the inside of the membrane, which burns off when the membrane reaches the right temperature.
Overheating the membrane will cause most roofing materials to smoke. If you are regularly bringing the membrane to its smoke point, you may need to have a professional change your propane torch regulator settings, or simply move the torch faster along the membrane. The neck tube length and burner head size can also be adjusted to vary BTU output, but only a qualified service person should make these adjustments.
The last thing you need to know about gas regulators is that they may freeze if you are roofing in cold weather. If your regulator appears to be frozen, you should not attempt to use it. Set it aside for the day and bring it to a qualified professional to see if the freeze has caused long-term damage.
Characteristics of Propane
Propane is the most common LP fuel used for roofing applications because it can achieve the necessary temperature, is relatively cheap and is readily available.
Propane and other LP fuels are compressed into the tanks and become liquids because of the pressure. When propane is released, it expands to 270 times the size it was in the tank. Though the tanks are small, they are deceptively heavy. If you are using a 100-pound tank, two roofers are required to move it.
Propane and other LP fuels are heavier than air, which means that they will collect on the ground unless the area is ventilated. When collected the propane may push away oxygen, preventing you from breathing, and increasing the risk of an explosion. To avoid workplace injuries, you need to ensure proper ventilation. The open air of the roof is enough ventilation, but storage containers may be too restrictive. This is why propane tanks should not be stored in closed areas, like truck cabs or sheds. Ideally, they should be stored outside.
You also need to take special precautions with propane when working in cold weather. In the winter propane flows more slowly, and the flame’s efficiency is reduced. Of course, the materials you are heating will be colder too, so they will take even longer to heat. You will need to plan for extra fuel if using a propane blow torch in cold temperatures.
Maintaining Your Roofing Gas Torch
You should maintain your gas torch and tank according to the manufacturer’s guidelines. However, there are some best practices, such as:
Roofing Gas Torch and Regulator Repair
Over time, you may find that any part of your gas torch has become damaged or is no longer working properly. The regulator specifically has moving parts and is subject to wear and tear. While some parts of a torch can be repaired others (like the regulator and hose) must be replaced.
Signs your roofing torch has stopped functioning properly include:
If your roofing gas torch seems to have problems, you should bring it to a qualified professional. This individual can tell you if the parts in question can be repaired or if they need to be replaced.
Roofing gas torches are ideal tools for many commercial low slope roofing applications. Understanding the torch’s components, especially the regulator, will help you operate the torch safely. It will also help you maintain the torch and identify when repair or replacement may be needed. Remember that safety should be your top concern when operating a roofing torch. Visit our commercial roofing section to learn more about heat welded membranes.
Learn more about IKO.
Editor’s note: This article was first published on IKO’s blog and can be viewed here.