Aluminum vs. Stainless Steel

[kurt]

.....for lining an old masonry/tile liner chimney that vents a reasonably modern (10 years old) steam boiler; 12 unit building.

I always say stainless, but a very reputable company (Willams Stoker) in my fair city is now installing aluminum.

Any sites, testing data, or other performance info?

[Jim Katen]

Originally posted by kurt

.....for lining an old masonry/tile liner chimney that vents a reasonably modern (10 years old) steam boiler; 12 unit building.

I always say stainless, but a very reputable company (Willams Stoker) in my fair city is now installing aluminum.

Any sites, testing data, or other performance info?

Gas or oil?

My understanding is that an aluminum liner will corrode when used with a oil burner. Have you asked Williams Stoker about this?

- Jim Katen, Oregon

[kurt]

Natural gas.

I've got my call in to WS. I was looking for some simple performance standard that I could reference, but they'll probably provide it.

[Chad Fabry]

IF it's gas and IF exhaust temps acn be kept above the dew point by properly sizing the flue then aluminum will work for a while.

There's no contest between aluminum and stainless in the resisting corrosion category. Stainless, even crummy stainless, wins every time.

The newer oils w/ lower sulfur content aren't as aggressive, but stainless is better and I believe is mandated by every oil burner co.

[Jim Morrison]

Kurt,

A couple of years back, I posed a similar situation to Chimney Bob and he thought stainless was overkill, though clearly the better material.

[Jim Katen]

Originally posted by kurt

Natural gas.

I've got my call in to WS. I was looking for some simple performance standard that I could reference, but they'll probably provide it.

Well, b-vents are all lined with aluminum. I thought aluminum was the standard for medium efficiency gas vents.

- Jim Katen, Oregon

[Chad Fabry]

Well, b-vents are all lined with aluminum. I thought aluminum was the standard for medium efficiency gas vents.

Nicely insulated, properly sized b vent+medium efficiency = exhaust temps above the dew point for a nice long life.

Lining a masonry chimney can certainly be done well w/ aluminum, but careful thought to flue sizing is paramount to getting the exhaust out before it condenses. That requires some savvy since one must also consider tons of masonry that needs to be warmed up for each heating cycle.

If they're fixing the liner in place with a portland base surround it's important to remember that aluminum and alkalies aren't the best of frinds either.

Acid on the inside, caustics on the out...here I am stuck in the middle w/you.

Usually, as a percentage of the total job, the difference in the price of materials is negligible.

[Kyle Kubs]

I'm in complete agreement with Chad. In the right conditions Alum. will last "long enough" and that is probably the key here. Stainless is the best way to do it but like the boilers that used to last 50-60 years, nowdays 15-20 is fine. And as Chad says, the probability of condensation is the key factor. If the boiler isn't sized right or set up properly it may short cycle a lot and the Alum. will be doomed in a short time.

[Brian Kelly]

One point that was brought up is the vent condensating in either SS or Alum. Both will condensate in certain conditions inside a brick or block chimney. In the NY area we tend to use SS and when needed the SS chimney must be lined (insulated) with the proper liner, manufactured by the liner company. I have only seen the insulation liner used in a few occasions and should have been used in many more. The chimney liner insulation kits should be used on all outside wall chimneys and even on certain inside chimneys.

[Bill Kibbel]

I'm quite sure al-oo-minium liners are fine unless it's a "cold" chimney (built entirely external).

A chimney, venting a Cat. I steam boiler sized to heat a 12 unit building, ain't gonna be cold.

A couple of years back, I posed a similar situation to Chimney Bob and he thought stainless was overkill, though clearly the better material.

If it's the same Bob I spoke with recently (we've both been speakers at a few of the same seminars), he's singin' a new tune. He now says only SS, unless it's down South.

[kurt]

Originally posted by inspecthistoric

I'm quite sure al-oo-minium liners are fine unless it's a "cold" chimney (built entirely external).

A chimney, venting a Cat. I steam boiler sized to heat a 12 unit building, ain't gonna be cold.

A couple of years back, I posed a similar situation to Chimney Bob and he thought stainless was overkill, though clearly the better material.

If it's the same Bob I spoke with recently (we've both been speakers at a few of the same seminars), he's singin' a new tune. He now says only SS, unless it's down South.

Bob Priesing? The same Chimney Bob that recently swept all the flues @ the White House?

That gentleman knows chimneys.

[msteger]

I vote stainless.