Frequently Asked Questions

Table of Contents

1. What are ISOMEMBRANE® seals made of?
2. What detail information do you need to manufacture seals?
3. We have limited detail drawings. How do we know that the seal will fit?
4. Who does installation?
5. Who does design?
6. What happens if an unforeseen challenge arises during a job?
7. How about emerging scope, i.e. an unanticipated expansion joint or hole in the penthouse roof?
8. How is "extra work" billed?
9. How can we be sure we will stay in our budget?
10. We are always pushed for time and have to work around other scopes. What kind of timeframes do you need?
11. Can you give us some specifics?
12. Okay on expansion joints. What about penthouse work? Typically, we have welders installing tubes and you know how territorial they can be.
13. What happens if we have a tube leak and damage the seal, or need to remove it?
14. Earlier, you mentioned performance benefits. How does that work?
15. We have some concerns about component overheating from attaching a membrane jacket.
16. You mentioned other cost justifications. Can you develop those points to help us get approval?
17. Balance of Plant?

ISOMEMBRANE® is a multi layer membrane comprised of stainless steel threaded studs, fender washers, nuts, mesh, hex metal, ISOBOND-E® (a proprietary, non-volatile adhesive), and ISOBLANKET-E®. Key materials have our specified properties, are tested and certified, by lot, to meet HTT criteria of heat resistance and strength. ISOMEMBRANE® is a completely non-RCF solution.

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In our design phase, we consider temperature, pressure and movement. Seal design is then formulated based upon tube or expansion joint arrangement.

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Materials are delivered to site in bulk, cut to fit specific component configurations, in accordance with membrane design criteria, and installed by certified technicians.

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Typically, we self perform installation using our experienced supervision and certified ISOMEMBRANE® technicians.

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Designs are generated by HTT.

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The HTT team has been miraculously responsive. With digital photography, electronic mail and ability to travel quickly, we have always been able to respond to emerging challenges.

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A principal benefit of ISOMEMBRANE® is that key materials are shipped in bulk, to site and can be tailored to emerging challenges.

Commercial agreements vary but typically we charge a mobilization fee and then bill actual work performed, on a unit price basis (per square foot). You pay for what you specifically ask to be done and confirm what has been installed.

Your designated site rep and ours will measure square footage installed, on a shift by shift basis, and this will represent our basis for billing.

Frequently, we keep customers informed on a shift by shift basis of amount expended (installed). Since ISOMEMBRANE® can be installed on a spot basis, a common strategy is to fix the worst first and continue as long as need, budget and schedule allow.

We are rarely the "critical path". We can virtually work right up until you need to close doors. Every additional leak that we stop will make a difference. As we do not require any demolition, you are never any worse off, or crippled from start up, as a result of our work.

Sure.

With expansion joints, sometimes we can actually make repairs on line.

Other times, a long weekend outage works to secure leaks that threaten full performance. If joints are sealed inside, this can provide considerable scaffolding savings.

We have frequently installed tube seals 3 or 4 assemblies behind the welding crew and generally, by the time they get their lead and gear pulled after weld completion, we can be done in another ½ shift. Planning needs to be such that new welds aren’t covered up for hydro or x-ray.

It is very easy to repair ISOMEMBRANE®. We can ship a care package overnite to repair, or generally respond with material and/or technical assistance as needed.

Proper combustion is key to optimum performance and mixing right amounts of air with available fuel, before the furnace exit, is essential to complete combustion. Air quantities are generally measured in the back pass (economizer outlet) and parasitic "sneakby" air in leakage, in the penthouse, will allow O2 monitors to read values higher than are actually available, to support combustion in the furnace. Optimum O2 values at the furnace exit (nosearch) are 3%. In actual traverse measurements, units with significant penthouse air in leakage have shown O2 at furnace exit 5% at monitors, when in fact furnace exit O2 was 0. This condition frequently is at the heart of high LOI in flyash, secondary combustion in the superheater, causing slagging, localized tube overheating and tube wastage from reducing atmosphere.

Fixing this is the BIG payoff.

Our overwhelming experience is that once flow is stopped, so is deterioration. Risk of overheating from high velocity gas pass far exceeds that of membrane application. With duct expansion joints, stopping air and water infiltration will tend to keep back-end components above acid dew point, extending life indefinitely.

Sure.

Housekeeping is an issue in most plants and with reduced budgets, janitorial manpower is squeezed for time. If flyash leaks are controlled, the plant stays cleaner. The advantages of less dust are obvious. A cleaner working environment makes it easier and healthier for plant employees. Lower dust levels mean longer life for motors and controls, too.

Thomas J. Rush
Copyright © 2004 [High Temperature Technologies, Inc.] All rights reserved.
Revised: 01/25/08.