Johns Manville Pipe Insulation, an Outdoor Shower, and a Lesson in Total Cost

If you’d told me that a small order of pipe insulation for an outdoor shower would change the way I quote rush jobs, I’d have laughed. It did.

Mike called at 2:40 on a Thursday, right after I closed out another order. He runs maintenance for a campground. The seasonal outdoor shower area was going to open in nine days. Over the winter, something had shredded the insulation on two exposed water lines under the deck. When Mike pulled back the old material, part of the jacket still had the Johns Manville name printed on it.

“I have to rip this out,” he said. “But before I do—does Johns Manville insulation contain asbestos?”

Does Johns Manville insulation contain asbestos?

I get that question a lot more than people think. Johns Manville is an old name, and in construction, “old” often means “possibly asbestos.” But the answer is not a one-line brand statement.

In current Johns Manville product lines, asbestos is not a listed component. The JM data sheets I keep on file for fiberglass pipe insulation, duct insulation, and rigid board insulation simply do not mention it. If someone buys JM material from a distributor today, I don’t expect asbestos to be an issue.

The problem is when you find material that was installed decades ago. Johns Manville has been around for a long time, and older high-temperature insulation products from many manufacturers used asbestos, including products that carried the JM name. So when Mike showed me a pipe covering that could have been from the 1960s, I didn’t tell him the brand made it safe. I told him to have a certified lab test a sample first. That is the only responsible way to answer the question for old installed insulation.

Finding the Johns Manville pipe insulation size chart

While Mike waited for the lab result, I started working on the replacement. The exposed lines were 3/4-inch copper. That detail matters because the Johns Manville pipe insulation size chart separates copper tube size from iron pipe size. If you guess “3/4-inch insulation” for a 3/4-inch copper line without checking the chart, you can end up with a piece that is too loose or too tight. I’ve made that mistake; I don’t want to make it on a tight deadline.

The chart was on JM’s website in a table that Mike wanted to forward to his installer. “I feel like an idiot,” he said, “but I can’t remember how to screenshot on Windows.”

Here’s the version I gave him: press the Windows key, Shift, and S at the same time. The screen dims and lets you drag a box around the area you want. When you release the mouse, the image goes to the clipboard. Open an email and press Ctrl + V to paste it. Mike captured the Johns Manville pipe insulation size chart in under a minute and sent it before we could get disconnected.

One more deadline trap: the glass cutter

Before we hung up, Mike asked one more question. The outdoor shower stall had a cracked glass panel, and he was thinking about cutting a replacement himself. “Would a glass cutter work?” he asked.

It depends, which is not what an emergency guy wants to say. If the panel is tempered glass, a glass cutter will not cut it. Tempered glass is made to break into small pieces when the surface is scored or damaged. If the panel is standard annealed glass, a glass cutter can work, but it needs a clean score and a straight edge. We checked the edge of the old panel and found the small tempering mark. No glass cutter was going to save that two-day lead time.

The real cost lesson

Mike’s lab sample came back negative late Friday. The old pipe covering did not contain asbestos. The test still mattered because neither of us could know that by looking at it. The cost of the test was small compared with the cost of a shutdown, a failed opening, or a crew exposed to asbestos dust.

The order itself was simple. A national online supplier had insulation for around $95 plus shipping, with an estimated Monday arrival. The local distributor had the Johns Manville material in stock for about $220. The local quote was higher, but Mike needed the outdoor shower ready for the Tuesday inspection. If the online package missed its connection, the crew would lose half a day and the inspection slot would move. The price difference was roughly the cost of one lost night. Local was the lower total cost, even though it was not the lower invoice.

I didn’t start out with that view. When I was newer, I would have picked the cheaper quote and hoped. Then you add reordering, expedited fees, and the angry phone call. Now I use a simple rule: calculate the total cost of the path, not just the sticker price.

That’s why the Johns Manville pipe insulation size chart is bookmarked. That’s why I don’t guess about asbestos. And that’s why I ask whether glass is tempered before someone pulls out a glass cutter. The pipe insulation saved Mike’s outdoor shower project; the changes in my own process are what stuck with me.