4 FM quick reads on grounds
1. Irrigation Issues: Upgrading for Savings
More maintenance and engineering managers nationwide are forced to deal with water restrictions when planning an upgrade of their irrigation systems, but the West Coast has been dealing with such restrictions for many years.
When Sandia National Laboratories in Livermore, Calif., implemented its computerized irrigation system in 2008, part of the motivation behind it was to more effectively comply with such water-reduction requirements.
The organization's science and technology research center, located 45 minutes east of San Francisco, features more than 300,000 square feet of landscapes, 50,000 square feet of hardscape, and 350,000 square feet of plantings over 13 acres of developed area.
Starting in 2007, the laboratory operated under a federal requirement to reduce its water use by 2 percent a year for eight years — a total that required a reduction of 16 percent, says Robert Holland, Sandia's environmental monitoring program lead.
The 2008 system was installed to help minimize unnecessary watering, Holland says. It measures wind and humidity, and when it senses rain, it shuts down within 10 minutes. With the previous system, irrigation could continue for six-eight hours before workers manually turned it off, resulting in hundreds of gallons of water being wasted.
"In 2009, we actually employed the flow-sensing device or option that goes along with the control system," says Gerald Vincent, the team lead for facilities at Sandia. "At that time, we made some additional changes with the master valves. When making the installation, that was a challenge.
"We weren't aware that there were additional equipment devices for the irrigation system that would go along with getting to the point of seeing the water management reduction we were looking for. The evapotranspiration (ET) base, we haven't used to its full capacity. We're bringing that online. There are several challenges there, but we're working through them with the local vendor."
Concrete Inspections for Long-Term Performance
Concrete sidewalks, ramps, parking lots and garages around institutional and commercial facilities can perform reliably for years. But they can do so only if maintenance managers implement a comprehensive concrete-maintenance program that identifies small problems early and addresses them before they become larger and more costly.
By developing inspection guidelines focused on common causes of problems, combining them with effective repair procedures, materials and equipment, and specifying coatings to protect surfaces, managers can extend concrete performance life and minimize trip-and-fall hazards.
Managers tackling the challenges of concrete maintenance must accept two contradictory facts: Water is a necessary ingredient in concrete, as well as its single most destructive enemy. Without a vapor retarder to keep water out, concrete coatings on below-grade inside floors or walls soon will fail.
Water expands by 9 percent when it freezes, causing spalling and cracking in exterior concrete walkways, floors, walls, and roofs. Concrete is alkaline and normally protects rebar from rusting, but water mixed with chlorides in de-icing compounds can penetrate to rebar and rust it, causing expansion and cracking. Water also can penetrate structural concrete beams and cause cracking, rusting the rebar and weakening the structure.
The first thing technicians must determine when inspecting concrete is whether the problem is structural or superficial. The start of a structural failure — for example, a deep crack in a structural concrete beam — requires immediate attention and documentation. A concrete engineer using non-destructive evaluation, such as ground-penetrating radar, infrared thermography, and impact-echo technology, can discover hidden problems.