October 6, 1996
How is radon gas measured?
Numerous techniques have been developed to determine the small concentrations of radioactive radon gas in the air.
"Because radon is an odorless, tasteless, inert gas that we cannot perceive, we need to rely on test devices and their operators to report the quantity of gas present in our homes," said Bruce Snead, extension specialist in residential energy at Kansas State University.
"Radon does, however, have a rather unusual property in that it is radioactive," Snead said.
Therefore, radon gas can be detected using radiological techniques.
One method involves recording the high-energy alpha particles emitted each time one of the radon atoms decays.
A second way is to base the experimental determination on the four radionuclides in the radon radioactive decay series. The four daughter products, in order of appearance, are polonium-218, lead-214, bismuth-214 and polonium-214.
Three types of measurement techniques have been used extensively for radon gas concentrations: time-integrated, continuous monitors and grab-sampling.
The grab-sample technique involves collecting the gas sample and performing a radon daughter analysis either on site or at a distant radiation-detection laboratory. This technique is rarely used in sampling in typical homes because it is a short-term snapshot of only a few minutes in one location.
Various continuous monitoring procedures can directly measure time-variant radon gas concentrations. Instruments of this type are more expensive but can plot the changes in radon over time.
Measurement specialists frequently use this type of device to measure homes.
The third and most popular method for recording environmental levels of radon is using time-integrated measurements. An example of this method is the collection of radon gas by adsorption onto charcoal. To use this technique, a small inexpensive canister or packet of charcoal is placed in the area to be tested — like the basement of a home.
After a few days, the container is sealed and sent to a laboratory for analysis. Gamma rays from the radon daughters, normally lead-214 and Bi-214, trapped in the canister, are measured by calibrated instruments.
"These devices can be purchased from local health departments, extension offices and retail outlets," Snead said. "Look for the term, "EPA-listed," on the package to determine if it meets EPA guidelines for quality assurance."
October 13, 1996
I need to have my attic insulated, but with all the concern about hazardous products and indoor air quality, I'm afraid to do anything for fear of jeopardizing my family's
health. Are there any insulation products I should definitely avoid?
"The most commonly used attic insulation products today include cellulose, fiber glass and rock wool," said Doug Walter, extension specialist in residential energy at Kansas State
University.
Precautions must be taken when installing these products to avoid breathing airborne fibers and dust, but once installed none of these present any known health hazards to a building's occupants.
"The gray color of some types of attic insulation, particularly cellulose, leads some people to believe that the insulation contains or is made of asbestos," Walter said.
Asbestos is rarely found in attic insulation unless it is a granular type of loose-fill insulation called vermiculite. Vermiculite is manufactured from a mica-like material mined in Montana and South Africa. Some samples have been found to contain small amounts of asbestos fibers.
"Vermiculite likely does not represent a health hazard unless it is disturbed, allowing asbestos fibers to be released into the air," Walter said.
High-quality respirators should be worn when working around any loose type of insulation to avoid breathing the fine fibers and particles that can be released when the insulation is disturbed.
"Insulation products already in place should pose no hazard to a building's occupants unless there are leaky return air ducts in the attic," Walter said.
Be sure to seal these return ducts before covering them with insulation.
Should I use a water heater insulation blanket with my new water heater?
"Residential water heaters must all perform according to minimum standards," said Gene Meyer, extension mechanical engineer in small business energy at Kansas State University..
For example, a 40-gallon, gas water heater must have an energy factor (EF) of at least .54, while an electric water heater must have an EF of at least .89.
"While this is a considerable improvement over heaters marketed just a few years ago," Meyer said, "there are water heaters on the market with EF ratings in the mid-60s or higher for gas and the mid-90's for electric.
Though there are many ways manufacturers improve the performance of water heaters, one common and cost effective method is to use better insulation around the tank.
"If you purchased a water heater that is on the low end of the efficiency rating, then it is still possible to cost-effectively reduce fuel cost by adding an insulation blanket," Meyer said. "However, if you purchased a water heater that is on the high end of the efficiency range, then additional insulation will probably not be of much benefit."
October 20, 1996
I plan to purchase a new gas water heater and install it in a location closer to where most of my hot water is used. I have no way of installing a chimney at this location.
Are there any gas water heaters available that don't require a chimney for venting the flue gases?
"All gas water heaters must be vented to the outside, but there are some models that don't require a conventional chimney or flue," said Doug Walter, extension specialist in residential
energy at Kansas State University.
One choice is a direct-vent water heater. This type of water heater can be vented directly through an adjacent outside wall, but the water heater must be no more than about six feet from the wall.
In a basement, the vent would be installed through the band joist, just above the top of the concrete basement wall. The vent pipe is double-walled, and outside air for combustion is drawn through the outer chamber. The combustion supply air also cools the vent pipe, protecting combustibles near the vent surface.
"Direct venting can be done only with special water heaters designed specifically for this method of venting," Walter said.
A second choice is a power vent, which uses a small fan to force the flue gases through a small pipe to the outside. This method allows greater flexibility in positioning the water heater because the water heater can be located further from an outside wall.
"The vent opening is smaller and less obtrusive than that required for a direct vent water heater," Walter said.
Power-vented water heaters are available as complete units, or power venting kits can be purchased for installation on conventional water heaters. Some modification of the control valve is required.
Is there more than one type of low-E glass?
Yes.
"The term low-E means low-emittance, and this refers to the window's transmittance of radiant energy," said Bruce Snead, extension specialist in residential energy at Kansas State University.
This type of glass has an extremely thin coating on one surface, usually the inner side of the exterior pane in a double-glazed unit. This coating reduces heat loss.
"This material has been very effective at improving the energy efficiency of windows and enhancing comfort by reducing the chill you may feel near window areas in the winter," Snead said.
There are three versions of low-E glass. One manufacturer puts a low-E coating on a thin plastic film and suspends the film between two panes of double-glazing. This creates an extra insulating air space, enhancing the unit's energy performance. "The other two types of low-E glass differ in the application of the coating," Snead said.
One is a hard coat (or pyrolytic) type, and the other is a soft coat (or sputtered) type.
"Data gathered to this point do not indicate a significant difference between the two in terms of performance," Snead said.
October 27, 1996
Should my water heater have a relief valve?
Yes.
"A relief valve in a water heater storage tank prevents the possibility of the storage tank rupturing should overheating increase the pressure in the tank beyond its limits," said Richard B. Hayter.
The relief valve is a safety device which should be installed on all storage-type water heaters. The valve typically is mounted on the top or on the side near the top of the water heater. Usually it is connected to a drain pipe which runs down along the side of the tank and discharges on the floor or into the floor drain.
This discharge line should be routed from the valve outlet to within about 9 inches of the floor to prevent scalding should the valve discharge when people are near it.
"If your water heater is not equipped with a relief valve, it is strongly recommended that you have one installed," Hayter said.
Some difference of opinion exists among various regulatory agencies as to the selection of these protective devices and methods of installation. As a result, it is essential that you comply with the manufacturer's instructions and applicable local codes.
If instructions are not available for your particular water heater or if codes do not exist for your locality, some general guidelines apply.
"First, the water heater should be equipped with a combination temperature-pressure relief valve," Hayter said.
You should select one that has a rating equal to or greater than the maximum hourly heat input rate of the water heater.
The heat input rate is typically listed on the manufacturer's nameplate, usually located on the exterior of the tank.
"Test your water heater's relief valve periodically to assure that it is not plugged," Hayter said.
When you test it, be sure that the water that is discharged will not damage any nearby items on the floor. If the relief valve has not been tested in a number of years, it may stick in the open position once it is tested.
"Therefore, be prepared to turn off the valves to the water heater and replace the relief valve," Hayter said.