Author of chapter on mold and mildew

By: Russell M. Keeler, PE

Regarding mold and mildew, I was looking through my library the other day and noticed a book on the subject, of which I was a chapter author.  The name is “Moisture Control in Buildings”, published by the American Society for Testing and Materials (ASTM).  This book came from a major arbitration on a resort hotel in the 1980s.  Soon after completion, mold was found throughout.  Each of the chapter authors served as a consultant to the defense legal team.  My chapter explains air conditioning equipment and the various air processes which cause condensation.

PEX tubing fitting deterioration
An interesting assignment involved PEX (cross-linked polyethylene) tubing.  PEX was installed in a residence, and when the water was turned on, it was found that the domestic water was unusable, as the water was blue, caustic and toxic.  My investigation disclosed that the cause of the problem was a combination of brass fittings (an alloy of copper and zinc) and water with a high pH.  The high pH caused the zinc to go into solution as zinc hydroxide.  While the pH does not directly attack the copper, some copper goes into solution and creates copper hydroxide.  Copper hydroxide is blue, caustic and toxic.  The solution to the problem was to treat the incoming water, as it was too expensive to replace the fittings.

Utility cost allocations
A common problem in mixed use developments (residential, retail, etc.) is the allocation of utility costs.  As developers try to minimize first costs of construction, the simple answer is to make the complex all-electric, so that each condo owner has an individual electric meter.  In higher end developments, this becomes a problem, as all electric is perceived as “lower end”.  A common solution is to use central gas fired hot water heat with gas appliances, with separate gas meters.  But…what to do about allocating heating costs?  Generally, natural gas costs are proportioned based on the design engineer’s estimate.  I was recently involved in such a project where some tenants disputed the allocation.  We performed additional calculations to verify the original allocations, then recommended a series of meters to more accurately assign costs.

Window replacement economics
There is much talk (and advertising) today about saving energy with new windows.  On a number of occasions I have evaluated the replacement of 1960s-1970s era windows.  It is true that new windows will save energy, but cost analysis discloses that the simple payback (window cost/annual savings) is in the 12-15 year range.  New windows will reduce drafts and maintenance as well as minimize the fading of interior colors.  All of these factors should be considered before replacing windows.  A higher efficiency furnace would be a wiser investment, and new furnaces have efficiencies as high as 96%.

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