Humidity in Schools: Too Dry or Too Damp?

It is like a Shakespearean play – damp or not too damp? That is the question. When is a school too dry or too damp? Both extremes can be hazardous to your child’s health and both need to be dealt with, but in completely separate ways.

This article from Indoor Environment Connections Online explains down the temperature turmoil.

Low-dewpoint winter weather often brings with it extremely dry indoor conditions, meaning schools that meet the recommended 15 cubic feet per meter of outside air could be experiencing 10 percent relative humidity in classrooms. These conditions often lead to the drying of mucous membranes and even nosebleeds.

There are several approved methods to deal with dry indoor conditions. These include:

  1. Make the building as airtight as you can so that it is not overly drying out all night long when not occupied.
  2. Do not over-ventilate it during occupied hours. That is, if the carbon dioxide levels are down around 600 parts per million at 11 a.m. versus 800 ppm in an occupied school on the coldest days of winter, you are very likely over-ventilating it and exacerbating any potential dryness problems.
  3. Do not run the ventilation system when the building is unoccupied. This includes exhaust fans as well as make-up air fans.
  4. Install enthalpy (total energy) recovery from the general building exhaust to capture some of the moisture from the occupants and put it back into the building.

Another way to combat respiratory issues is to clean the air in which we breathe. This means removing dust and other airborne debris. This can be accomplished by:

  1. daily use of auto scrubbers (with clean water) on hard-surface floors;
  2. daily use of vacuums with high efficiency bags and good suction on carpets and hard surfaces;
  3. if dry mops are used, they must be treated, or they make dust clouds; or
  4. use of some of the new microfiber dusting devices, or damp-wiping.

Unfortunately, dry indoor conditions are not the entire problem. Extremely damp conditions are also causing respiratory problems in schools. Damp areas facilitate the growth of mold, which can be extremely hazardous when inhaled.

There are only two methods for dealing with extremely damp areas.

  1. Fix number one, stop the liquid water intrusion, or manage it in a way that porous materials stay dry, and routinely clean the hard surfaces like you would clean your bathroom fixtures.
    1. Drying: We know of two means for drying surfaces: Add lots of heat, or make air dry by dehumidifying it. In the winter heating up the space and allowing dry outdoor air to enter it will usually give you dry air and good drying potential. During the rest of the year, a good high capacity energy efficient dehumidifier such as a Thermastor Sierra, or one of their competitors, should do a great job at drying any surface by increasing the drying capacity of the air. We define a high capacity unit as one that gets you in the range of 100 to 140 pints a day of moisture for less than 10 amps of power with a 115 volt power source.
    2. Isolation and exhaust of dampness: In some cases, crawlspace dampness can best be addressed by installing a sub-membrane radon removal-type system to capture dampness from the earth below a smoke-rated plastic sheet and dumping it outdoors. Lots of information is now available regarding keeping crawlspaces sealed up, warm and dry, versus the typical vented and damp and cold.
  2. If the source of the liquid water has been addressed, the effects of dampness can often be remediated by keeping paper products away from the damp area and either warming the surfaces in the area above the dew point of the air, or drying the air to lower the dewpoint.

If these problems persist, call a specialist as soon as possible. Respiratory problems, especially those caused by outside irritants, like mold, should not be ignored. If your child experiences any abnormal breathing problems, consult your primary car physician immediately.

If you have any questions, contact Advance Mold Remediation by calling 1-877-411-MOLD or click here today!

This entry was posted on Wednesday, June 1st, 2011 at 9:37 am. Both comments and pings are currently closed.

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