InTents December 2020/January 2021 - 38

business | safety

Winter challenges:
heating and air filtration
How to keep tents, buildings, warehouses and other structures
warm and dry during the COVID-19 pandemic.
by Daryl Benz

eating tents and other temporary
structures is always a challenge
whenever the weather gets colder. But
factor in the pressures of combatting
COVID-19 and you have a potentially
complex situation on your hands.
The Centers for Disease Control (CDC)
and the American Society of Heating,
Refrigerating and Air-Conditioning
Engineers (ASHRAE) have recommended three core measures to improve air
quality in buildings and structures of all
kinds, whether permanent or temporary. You will need to focus on bringing
in more fresh air from outside, increasing your circulation to around four to six
air changes per hour, and introducing
extra mechanical air ϐiltration measures.
All of these are achievable, but when you
combine them with seasonal heating requirements, you'll need a bit of creative
planning to get it right.

H
Three steps for improved air quality
The CDC and ASHRAE (the global society
for HVAC air quality and sustainability)
have issued the following guidelines to
improve the air quality in enclosures:
* Increase the percentage of outdoor
air that circulates into the system.
* Increase ventilation rates, or
" air changes " per hour.
* Introduce mechanical support
for return air systems, such as
high quality ﬁlters, UV lighting
and air scrubbers.

Warm air concerns
Let's say you decide to use an indirect
heater to blow warm air into your tent,
for example. This helps you to get more
fresh air in, so that's one box ticked. But
it also causes a number of problems.
First, warming up fresh air takes
more energy than reheating return air
through an HVAC unit, which can make
it very expensive to heat. You also need
to be very careful about where you're
actually sourcing the outside air from.
The aim is to bring clean, fresh air into
38 intents

1220IT_36_CV4.indd 38

the building, so make sure you aren't
drawing it from a source point near a
crowd, a dusty ϐield or a dumpster.
Second, ϐiltration of the air on an
indirect system can be problematic.
You can't simply put an air ϐilter on the
supply side to clean the hot air as it's
fed into the tent because it's too hot and
will melt or burn. Also, most indirect
units have no means for adding a ϐilter
to the heater's return, so you can't
mechanically ϐilter the air, according to
industry guidelines. And, to make things
worse, you're blasting that hot, fresh air
right through the tent to get it to the
colder areas. If there are any airborne
contaminants or viruses inside your
tent, these will be circulated, too.
Meanwhile, direct-ϐire heaters are
notoriously bad for releasing moisture
into the air, and humidity is a big
problem when you're trying to control
the spread of disease. Damp air is a
real issue when you're trying to avoid
misting over plastic masks, face shields,
dividers and other personal protective
equipment (PPE).

Solutions
How should you tackle these challenges?
One simple improvement is to use a
hydronic heating system. Hydronic
heaters run hot water through pipes
along the outside walls of a structure, and
use air handlers to distribute a dry heat.
More importantly, fresh air in the interior

dec 2020-jan 2021

11/19/20 4:00 PM
InTents December 2020/January 2021

Table of Contents for the Digital Edition of InTents December 2020/January 2021
