Corrugated Stainless Steel Tubing (CSST) - The New Gas Line

Several months ago I wrote a blog about how great PEX tubing is, and today I'm going to discuss the equivalent for gas piping - Corrugated Stainless Steel Tubing, which is commonly referred to as CSST.  This is a product that can be used for the distribution of natural or LP gas throughout buildings.

A very brief history of CSST


CSST was invented in 1988, and gained approval for use in all commercial and residential installations throughout the United States in 2003.  Since then, CSST has quickly gained in popularity, and is estimated to be used in more than half of all new homes built today.





The main attraction to CSST is that it's flexible and relatively easy to install when compared to standard gas piping.  The fittings for rigid gas piping need to be tediously screwed together, and the piping itself must be measured, cut, reamed, threaded, then cleaned.  With CSST, the piping just gets cut to length and a fitting attached to the end.  It's easy to understand why it has become such a popular product.

CSST doesn't seem to be as popular in Minnesota

Unlike many other parts of the country, Minnesota allows the use of flexible soft copper for gas piping.  The installation procedure for flexible soft copper is comparable to CSST, making it far easier to install than rigid gas piping.  For plumbers in Minnesota that have always installed soft copper and are comfortable doing it, I'm guessing there's probably no point in changing products.  CSST is also more expensive than standard gas piping or flexible copper tubing.

Another reason that I probably don't see as much of this material is that it's not readily available to the handy homeowner.  While most building products can be easily purchased at any home improvement store, CSST can't.  That's probably a wise thing for the CSST industry, because it means there will be less improper / unskilled installations.

How to identify CSST

CSST looks similar to a gas connector, but is easily distinguished by a flexible yellow polyethylene jacket on the outside.  Gas connectors will often have a coating on the outside - not a jacket.  CSST will also be identified as such on the jacket itself.  The most common type of CSST that I see here in the Twin Cities is Gastite - in fact, that's all I can ever recall seeing.

CSST Installation Requirements

The general rule for CSST is that it must be installed in accordance with the manufacturer's instructions.  Because I only see Gastite CSST, I'm listing a few of their installation requirements.  Every other manufacturer has similar requirements.  These requirements come directly from Gastite's 102 page installation manual (fun reading).

• Tubing shall be supported in a workmanlike manner with pipe straps, bands or hangers suitable for the size and weight of the tubing, at intervals not to exceed those shown in Table 4-3.   The referenced table requires support every 4' for 3/8" pipe, every 6' for 1/2", and every 8' for anything larger.  "J" Hooks may not be used.
• Tubing routed on top of ceiling joists and other structural members which comply with the horizontal support spacing requirements will be considered sufficiently supported.
• Any portions of the exposed stainless steel tubing shall be wrapped with tape or sleeved to prevent threats by acids or chloride based cleaning solutions for masonry. Self-bonding silicone tape is recommended here for durability.
• The Gastite® Mechanical Fittings have been tested and listed per the requirements of ANSI LC-1 for concealed use.  I include this reference because I've heard other home inspector say that the fittings are never allowed to be concealed.  The manufacturer says they are.
• Outdoor installations - Along side a structure – When installed along the outside of a structure (between the ground and a height of 6 ft.) in an exposed condition, the CSST shall be protected from mechanical damage inside a conduit or chase.
• When it is necessary to install Gastite through masonry materials the tubing shall be routed through a conduit that is a ½" larger in diameter (to ease routing) than the OD of the CSST and appropriate for the application. The sleeve must maintain a continuous watertight barrier between the masonry material and the CSST, up to or past the edge of the masonry hole.
• Where all three of the following conditions exist mechanical strike protection must be used: Concealed, Constrained, and Within three inches of a potential thread.  That means strike plates must be used.
• For use with movable appliances, Gastite® must be rigidly terminated before the appliance connection. This means CSST is not an acceptable substitute for an appliance connector.
• Where it is necessary to install Gastite through sheet metal enclosures (such as fireplaces) the tubing should be routed or supported to prevent physical contact with the enclosure. If direct contact cannot be avoided a rubber grommet may be used to prevent physical contact with the enclosure. Otherwise a Gastite angle stub or rigid pipe components must be used.
•  Direct bonding of Gastite® CSST is required for all gas-piping systems incorporating Gastite® CSST whether or not the connected gas equipment is electrically powered.  This last item has been the topic of many blogs and articles, and is apparently one of the more important things to look for.  Gastite has a great video on their web site showing how it's done - click here to see it.

Reuben Saltzman, Structure Tech Home Inspections - Email - Minnesota Home Inspections


    

Gas Appliance Connectors

I recently wrote a blog about the most common places to find gas leaks, and I said I'd follow up with a blog about gas connectors - those short, flexible, corrugated things that are used to connect gas appliances to gas piping.  Today I'll go over the items that I look for on gas connectors while doing home inspections.  I'll cover the most common installation defects, and I'll go over the differences between new and old connectors.


Gas Connectors are not a substitute for gas piping. To start, here's a photo of a gas connector - it's that corrugated yellow thingy.  Most newer gas connectors look just like this one.  Remember, a gas connector is used to get from the gas piping tothe appliance - that's all.  Gas connectors should never be used as a substitute for gas piping.  This means that if you ever see two connectors joined together, it's an improper installation.  If you hear someone call this a flexible gas line, smack 'em upside the head and gently correct them.  It's not a gas line, it's a gas connector.


Gas Connectors should never disappear in to a concealed location.  If a gas connector disappears in to a wall, floor, ceiling, or cabinet of an appliance, it's an improper installation.  Only proper gas piping should be run through walls, floors, cabinets, etc.

 

Gas Connectors need to be sized appropriately. I stopped by my favorite orange box the other day to check out their selection of gas connectors, and they had three sizes available - low demand, moderate demand, and large demand connectors.  It's alright to go larger, but not smaller.   The size and length of the appliance connector is determined by the BTU rating of the appliance.  Most jurisdictions allow six foot connectors for ranges and clothes dryers, and three foot connectors for everything else.



Old Gas Connectors should be replaced. The current standard for gas appliance connectors is ANSI Z21.24.  I tried to get a copy of those standards for this blog so I could say what what makes the newer connectors different, but it would have cost me almost $600 (get out of here!), so I did something even better.  I got my hands on a new gas connector and an old one, and I cut 'em open.  Here's what I found.



As you can see, they're made from different materials.  The new gas connector, which complies with ASNI Z21.24, is made from stainless steel.  The old connector obviously isn't - it's made from brass.  To quickly spot the difference between the old and new connectors, you can usually just look at the outside jacket.   Old connectors will typically have a grey coating, like the one shown above left, a braided stainless steel jacket like the type shown below, or they'll obviously be made of uncoated brass like the one shown far below.



Newer connectors are typically coated with yellow, like the one shown at the beginning of this blog, or will be plain stainless steel, like the one pictured at the bottom of the photo below.  If the connector has a grey coating or is made from uncoated brass, it's old.



To know for sure, you can look closely at the nut, or sometimes at a ring that has been attached to the connector.  If it meets ANSI Z21.24, it will say so.



If a gas connector doesn't meet this standard, it should be replaced.  The older gas connectors are much more prone to leakage, making them a latent hazard.  I've never found one that leaked, but I've heard that when they leak it's a major event.  The Truth-In-Sale of Housing programs for Minneapolis, Bloomington, and several other cities require replacement of these old connectors.  You can click here for Bloomington's position on old gas connectors.

Don't reuse gas connectors. According to every manufacturer, gas connectors should never be reused.  When a gas appliance is replaced or disconnected, the connector should be replaced at the same time.   This isn't something I look for during home inspections, just a good tip.  Oh, and one other thing - don't confuse gas connectors with Corrugated Stainless Steel Tubing (CSST).  They're not the same thing, and they're never interchangeable.   I'll have a good blog about CSST next week.




Reuben Saltzman, Structure Tech Home Inspections - Email - Bloomington Home Inspections
    

Where To Look For Gas Leaks

The one home inspection item that consistently causes home buyers to 'freak out' more than anything else is a gas leak. Gas explosions like the ones that recently happened in Edina and Saint Paul are probably the main causes of all the paranoia about natural gas.  Believe it or not, small gas leaks are actually quite common at old houses, and they're usually simple for a plumber to fix.  Today I'll share the most common locations for gas leaks, and I'll share my home inspection techniques for finding gas leaks in old Minneapolis and Saint Paul homes.

The most common place for me to find gas leaks is at gas valves.  Older style gas valves that aren't allowed any more today are often referred to as lube valves or plug valves.

 

These valves are easily identified by a nut or spring on the valve, across from the handle; newer gas valves don't have these.  I would estimate that I find leaks at about one out of every five of these valves.  Gate valves, which should only be used for water, are also common offenders.



The repair is always simple - replace the the valve.  In Minneapolis, if the appliance being served by an improper valve is replaced, the valve must be replaced at the same time.

The second most common location for gas leaks is at unions.  A gas union is a fitting that provides a disconnection point for a gas appliance.  If the union doesn't get tightened enough, it will definitely leak.  Notice the bubbles in the union below?  That's a small gas leak.



Flare fittings are the last common offender.  Here in Minnesota, soft copper gas tubing is allowed just about anywhere, but it takes a little more skill to properly install soft copper than other types of gas piping.  For a flare fitting, copper tubing gets flared out at the end and connected with a flare nut.  If this connection gets bent or isn't tight enough, it will leak.

  


To find these gas leaks, I mostly rely on my nose.  If there's a gas leak, I can almost always smell it.  To pinpoint the location of a gas leak, I use a combustible gas detector.  If I see any suspicious work or I run across old or improper gas valves, I just go right to my gas detector, and I quickly check the fittings.

I truly believe that my nose is just as accurate as my gas detector, but I look a little silly running my nose along gas pipes to find leaks.  That's why I use a tool.  If I find a leak with my combustible gas detector, I confirm the leak by using a gas leak detection solution; it's just an expensive blue liquid that does about the same thing that dish soap would - it bubbles if there's a leak.  To make it easier for the repair person coming in behind me, I also mark the location of the leak with orange electrical tape, and I write "Gas Leak" on the tape, along with an arrow showing exactly where the leak is.

I've heard stories about appliance connectors leaking, but I've never found one that leaked. Next week I'll talk about defects with appliance connector installations.

RELATED POST: Natural Gas Leaks

Reuben Saltzman, Structure Tech Home Inspections - Email - Home Inspector Twin Cities
   

Electric Baseboard Heaters - The Flipper Favorite

When I inspect a home in Minneapolis or Saint Paul that has electric baseboard heat, it's usually a dead giveaway that someone did some remodeling, or someone flipped the house.  In fact, the only houses that I run across in the Twin Cities metro area with all electric baseboard heaters are houses that have been 'flipped'.   Why?  I'll get there.

The times when electric baseboard heaters make the most sense to install are when someone wants to add heat to a room that won't be used frequently, and they don't need air conditioning.  One common place for Minneapolis and Saint Paul houses would be basement bedrooms that get added as guest bedrooms.  Another would be additions that just don't stay as warm as they should.   I added a couple baseboard heaters to a sun room at my own house that doesn't get very good air flow from the furnace, and I turn the heaters on when the temperature drops below zero outside.

The nice thing about electric baseboard heaters is that they're easy to install, they don't cost much, and there isn't a lot that can go wrong with them.  The only failure I've found during home inspections is that the thermostats have gone bad, and this isn't a difficult fix.  Most of the problems that I write up during home inspections deal with improper installations.  I've listed the two most common offenders below.

Outlets Installed Above The Heater All manufacturers of electric baseboard heaters prohibit the installation of electrical outlets above the heaters.  Electric baseboard heaters work by turning a heating element on and off; it's either hot or it's not, nothing in-between.  Because they get so hot, an electric wire draped in front of a baseboard heater could potential melt or start a fire.\



Improper Clearances Electric baseboard heaters require certain clearances above and in front of the units to anything combustible, such as drapes.  Again, the reason for this is to prevent a potential fire.   The clearance requirements vary - just check out the two diagrams below from two different manufacturers.  One says twelve inches, the other says six.

 

These clearance requirements shouldn't be taken lightly.  The photo below came from a recent inspection where the drapes looked like they were about to burst in to flames.



So why are baseboard heaters a favorite of the fix-n-flipper? They're cheap and easy to install.  On the downside, electric baseboard heaters cost far more to operate than a gas fired furnace... but why would the person flipping the house care?  They won't be paying the heating bills. For homes in rural areas where power companies offer off-peak discount rates for electricity, electric baseboard heaters might make sense as the primary source of heat, but not here in the heart of the Twin Cities.

Reuben Saltzman, Structure Tech Home Inspections - Email - Home Inspector Twin Cities
    

How Serious Is A Cracked Heat Exchanger?

It's an industry standard: if a furnace has a cracked heat exchanger, it gets replaced.  The American Gas Association has even put this in writing - they say "Any visible crack or hole is reason for requiring replacement of the heat exchanger or furnace."  When I inspect a furnace and I find a cracked heat exchanger (and I find a lot of them), I always say to replace it.

So what's the big deal with cracks or holes?  The concern is that a cracked heat exchanger could allow exhaust gas from the furnace to contaminate the household air with carbon monoxide.   In order for this to happen, the furnace must be producing high levels of carbon monoxide AND the exhaust gas must be mixing with the household air.  For a good example of a hazardous heat exchanger, check out the photo below showing a large rust hole in the heat exchanger of this high-efficiency furnace that was only ten years old.




Cracks, on the other hand, I'm not so sure about.  With the majority of the cracked heat exchangers that I've seen, I've always been curious how the exhaust gas from the furnace could possibly leak out of those tiny cracks enough to contaminate the househouse air.  Of course, what I'm curious about doesn't matter... but sometimes my curiosity gets the best of me, and I have to find out for myself.

So I did. I took home a furnace that had a cracked heat exchanger, and I removed the heat exchanger cell that had the largest cracks.  You can see the cracks for yourself below - click on any of the photos for a larger version.  This first photo shows the cracks as seen from inside the heat exchanger cell - this is what we saw during our inspection.



These next two photos show the cracks from the exterior, or blower side of the heat exchanger cell.  This part of the heat exchanger is usually not visible during the course of a home inspection.

 

I wanted to see if water would leak through these cracks, so I doused the outside of the heat exchanger and looked inside for any signs of leakage.  Nothing.

I've heard that penetrating oil, such as WD40, will get through the cracks, so I tried that next.  Nothing.
Feeling pretty disappointed at this point and determined to get some results, I filled the heat exchanger with water.  I laughed like a mad scientist at what happened next.



Water began to leak out of the factory seam in about ten different places, but the crack never leaked.
Why does this tiny crack mean the furnace should be replaced?  I've heard that when heat exchangers get very hot, the metal expands and the cracks open up, allowing air to leak in to or out of the heat exchanger.  Just because my test didn't allow any water to leak doesn't mean that this furnace was safe, and it doesn't mean that a different furnace will behave the same way... but I sure found it amusing.

Maybe I need to get out more.

RELATED POSTS:

• Furnace Certifications Might Be Useless
• Does A Better Inspection Increase Liability?
• Houses Don't Need CO2 Detectors

Reuben Saltzman, Structure Tech Home Inspections - Email - Twin Cities Home Inspector