Inside
Insights
Humidification
With Steam:
Go ahead and breathe easy!
Steve Tredinnick, PE, Vice President of Energy Services, Syska Hennessy Group
humidification is not a luxury but commonplace. But then you have to wonder, what
is in that steam, and is it truly healthy for
us to breathe? I mean, isn’t steam loaded
with foul and nasty chemicals to keep pipe
corrosion to a minimum?
As the reader is probably aware,
humidification is moisture added
to the air to assist not only with
thermal comfort and respiratory
health, but also mitigating
static shocks, etc. Many times
steam is injected directly into
the air stream in lieu of atom-
izing cold water.
Editor’s Note: “Inside Insights” is a column designed to address ongoing issues
of interest to building owners, managers
and operating engineers who use district
energy services.
As I write this edition, I am freshly
back from the IDEA Annual Conference & Trade Show in Orlando and
the ASHRAE Annual Meeting in Salt Lake
City. The ASHRAE meeting was similar to
last year’s IDEA annual conference, as I
experienced more of a dry heat (much like
Jim Lodge’s beloved Phoenix for last year’s
venue!).
In contrast, at IDEA’s conference in the
steamy heat of Orlando, I started to glisten
like a cold beer straight from the fridge.
Once it gets above 70 degrees F, I tend to
sweat like a pig, as I have had too many
years in the frozen tundra of the Upper
Midwest to acclimate quickly to southern
climes. It’s not that I miss winter so soon
after bidding it good riddance, but the thing
with winter is, if it gets too cold, you can
just put on more layers. Conversely, when
it gets too hot, I can only take off so much
before it gets obscene, and I start looking
like a very monochromatic bleached version
of Shamu.
Thinking of humidity reminds me that
it’s something we sorely lack in our office
during the winter months. The extremely
dry winter air causes a great deal of static
shocks. I cannot tell you how many times I
have locked my computer up solid with a
nice little carpet shock. Nothing gets me
more steamed than computer problems.
Speaking of steam, I often think of my
Syska brethren in the New York office connected to the Con Ed steam system where
As it turns out, I have nothing to fear,
but the answer is not that simple. The steam
used for direct humidification must be certified for use by the U.S. Food and Drug
Administration (FDA). This means that it is
either chemical-free or it uses FDA-approved
additives below maximum allowable concentrations. To confirm my research, I surveyed several IDEA member steam systems
to get a feel if there is an industry-standard
practice. But before I delve into my survey
results, I should briefly explain why chemicals
are required in the first place.
Carbon steel and copper alloy pipe
corrosion can occur due to the presence
Table 1. Current Permissible Amine Concentrations in Air in U.S. (Per per the U.S. Food and Drug
Administration, American Conference of Governmental Industrial Hygienists and the National
Institute for Occupational Safety and Health.)
Substances
Cyclohexylamine
Limits
Not to exceed 10 ppm in steam and excluding use of such steam
in contact with milk and milk products.
Diethylaminoethanol
Not to exceed 15 ppm in steam and excluding use of such steam
in contact with milk and milk products.
Morpholine
Not to exceed 10 ppm in steam and excluding use of such steam
in contact with milk and milk products. Does not carry very far in
the steam distribution system and typically will stay within the
plant. (University of Michigan limits to 0.7 ppm; OSHA limits to
20 ppm.)
Octadecylamine Not to exceed 3 ppm in steam and excluding use of such steam
in contact with milk and milk products.
Source: Code of Federal Regulations CFR 173.310.
