ACHRNEWS

Let it snow, shovel-free

June 1, 2000
It’s snowing outside. The wind chill factor makes it feel below zero. Even though your radiant floor heating system is keeping everything indoors warm and comfortable, what about outdoors? The idea of shoveling the driveway and walk doesn’t seem so appealing.

A solution is at hand, though.

The same principal of heating a surface and allowing the heat to radiate upward can also be applied outdoors to melt snow and ice. Installing a hydronic snow- and ice-melt (SIM) system underneath driveways, sidewalks, stairs, loading docks, wheelchair ramps, and medevac helicopter landing pads, for example, can keep them snow- and ice-free all year.

Other benefits

In addition to keeping facilities accessible, SIM systems provide a range of other benefits. The most obvious is the time and effort involved with snow removal, but that’s just the beginning.

The costs of buying, storing, and applying salt and sand are eliminated. Also, both salt and sand deteriorate stone and mortar over time, which can result in repair costs.

Additionally, these melting agents are tracked into homes and buildings on boots and shoes, damaging floors and carpeting. In commercial applications, SIM systems have been shown to reduce commercial carpet replacement by as much as one-half to two-thirds.1

A SIM system may also lead to a decrease in the number of liability claims; quickly removing snow and ice may reduce the likelihood of injurious slips and falls.

Hydronic SIM systems can also aid municipalities in complying with the Americans with Disabilities Act (ADA), which requires that private businesses and municipal buildings be accessible to persons with disabilities.

SIM systems help ensure that wheelchair loading ramps and exposed subway and bus platforms are passable in inclement weather.

Weather dictates system design

Weather conditions affect the type of system that is required. Average outdoor ambient temperature, both during and after snowfall, and wind speed are the primary considerations.

Very cold air generally contains little moisture. Although many people associate snowfall with cold air, the wind chill factor often makes the air seem colder than it really is. Snow is rare when the temperature is 5°F.

However, just as your body burns more energy to counter the effects of a wind chill factor, SIM systems must work harder to melt snow in windy conditions. Then again, spring snows can be wet and heavy, and also require more melting energy.

All of these conditions must be considered in system design.

When designing a system, weather data are examined to determine the average snowfall per hour and average temperature during snowfalls, including the wind chill factor. The system is then designed to remove snow during those conditions.

Accommodating the worst conditions requires that system capacity be increased by closer pipe spacing, or by installing a heat source capable of heating the fluid to higher-than-normal temperatures (but not beyond the tolerances of the surface medium). While the heat source can usually be upgraded at a later time, pipe spacing literally is set in stone.

SIM automation

One of the biggest assets of a SIM system is its versatility. Acceptable levels of snow accumulation vary according to the application.

What may be acceptable on a residential driveway may not be acceptable on a loading dock, and definitely is not acceptable at an emergency room entrance or medevac landing pad.

Once the system is installed, several options are available for operating it, the simplest being an on/off switch. While economical, someone must always be available to activate and deactivate the system.

More common are timer-based systems, which operate similarly to the timers used to activate home lighting. For example, if a snowstorm is expected overnight, the system can be programmed to engage at 1 a.m. and run for 8 hrs.

The most advanced systems are fully automated. Sensors monitor temperature and humidity levels. The system engages automatically when predetermined temperature and moisture parameters are met.

Often these systems are kept at a minimum idling temperature, to ensure quick system response when snowfall begins.

The roads may not always be snow and ice free, but with a SIM system, the pathways to your home and building can be.