What happens when you introduce new supplies of natural gas to a furnace that is not properly adjusted?
Flashbacks, a rise in carbon monoxide levels and flames lifting off the burner, to name a few problems.
It's an issue state regulators and Salt Lake-based Questar Gas Co. officials are grappling with as new compositions of natural gas reach Wasatch Front homes.
The so-called lower-heat-composition gas reaching the Wasatch Front prompted Questar Gas five years ago to build a processing plant near Price to make the new supplies safe for customers.
But a 2003 Supreme Court decision and subsequent 2004 order by the Utah Public Service Commission forced the utility to refund roughly $29 million it had collected from customers to pay for the plant.
Today, the plant continues to operate at the utility's expense as a 2008 shutdown target approaches. At that time, a complete changeover to lower-heat-composition gas will be launched, and the processing plant will be retired.
The big question is what to do about customers' furnaces.
"Do the furnaces indeed have to be reorificed, and if so at what level?" public service commissioner Ted Boyer asked Wednesday. "How can we get that accomplished least expensively and quickly to minimize the safety issue?"
On Wednesday, the commission opened the first of a series of meetings to find answers.
Boyer said some options, like injecting propane into the pipeline system to raise the heat content of the gas, are being considered.
Historically, natural gas supplies along the Wasatch Front had a higher heat composition, or BTU rating. That changed as the natural gas pipeline system became increasingly interconnected.
In fact, there are roughly 250 varying compositions of natural gas that reach the pipeline system today, according to Larry Conti, manager of gas management at Questar Regulated Services.
Those varying compositions demand a daily balancing act by the utility to ensure gas content falls within the operating range appropriate for appliances.
The company's ongoing strategy since 1998 has been a "green-sticker" campaign to alert the public to have gas-burning appliances checked and possibly adjusted by licensed professionals.
As of Sept. 30, roughly 43 percent of Questar's 750,000 Utah customers have had their appliances checked and received a green sticker. A survey also indicated that 73 percent of customers were aware of the issue, while 27 percent said they were unfamiliar with the campaign.
Tony Oakman, president of Salt Lake-based Lee's Heating and Air Conditioning, said there are many older furnaces along the Wasatch Front.
"If there is improper venting or any kind of problem within the furnace where it cracks and it's making carbon monoxide, the chances of carbon monoxide poisoning are severely increased," Oakman said. "Probably the most common problem is a dirty furnace. We find flue code violations all the time and improperly vented furnaces."