SOOT SOLDIERS : A dirty chimney is not only messy but also a fire hazard. As we enter the cold months, a professional inspection is probably a good idea. Here’s what to look for and what to expect.

Grimy men dancing about London rooftops and singing at the tops of their lungs has endured as a popular image of chimney sweeps ever since Dick Van Dyke swept away our hearts in “Mary Poppins.”

Like most Hollywood images, however, a dancing chimney sweep is not even close to reality. For one thing, the drop is just too far, said Rob Lewis, co-owner of Red Hot Chimney Sweeps and Fireplaces in Orange. “I fell off a two-story roof, but luckily a tree branch broke my fall and didn’t do more than twist my ankle.”

Falling, however, is actually uncommon. Soot is much more of a danger to professionals who clean chimneys.

“Long-term exposure to carcinogens is the biggest problem, so we pay close attention to make sure soot is removed from our bodies quickly. We always wear breathing masks and take lots of showers,” Lewis said.

Unlike their predecessors, modern chimney sweeps do not usually hold small orphans by their ankles so they can climb down the chimney flue to clean. However, in a nod to tradition, many still wear top hats and tails.

“It’s an old German tradition,” Lewis said. “Most chimney sweeps are now all California’ed out, or they wear nice new top hats.”

In an attempt to look clean in a dirty business, chimney sweeps in the 1800s got clothes from undertakers. “Black is a great color because it can look clean even when it’s dirty,” Lewis said.

But proper attire is not the most important element of a good chimney sweep--what is crucial is an in-depth knowledge of chimneys, fireplaces and fires.

A dirty chimney can be a fire hazard. Creosote, the sticky substance that remains after a fire, is highly flammable.

Also, a clean chimney reduces the chance that toxic gases and carbon monoxide produced by the fire do not escape into your home.

The Chimney Safety Institute of America has information on chimney sweeps and chimney safety and can be called at (800) 536-0118.

When to Sweep

Luckily in Southern California, where fireplaces are used more for atmosphere than keeping rooms warm, cleaning does not have to be a yearly expense.

“There are some unscrupulous people out there who will tell you your chimney needs cleaning when it really doesn’t,” said Randy Cannady, co-owner of Pro-Tech chimney cleaners and builders in Santa Ana. “People here use their fireplaces what, three months out of the year? We recommend at least an inspection and possibly a cleaning every three to five years.”

A rule of thumb is to have the chimney checked after you’ve burned two cords of wood.

One way to tell if a chimney needs cleaning is to inspect the flue. “If you can take your finger and write your name in the soot, it’s definitely time for a cleaning,” Cannady said.

Once you determine that the chimney needs cleaning, call a professional. “Homeowners shouldn’t try to clean a chimney themselves,” Lewis said. “Not because I’ll lose money but because they don’t have the proper equipment or expertise.”

Chimney sweeps charge $65 to $80.

In the Dust

There’s no need to cover furniture in a room or remove pictures from walls when your chimney is being cleaned. A professional chimney sweep needs only about 3 to 5 feet in front of the hearth to do the job.

Typically, either a tarp is laid in front of the hearth or a tent is placed over the entrance to the firebox.

A double suction vacuum is placed in front of the firebox and runs while the chimney sweep sends his brush down the chimney. If the firebox and smoke shelf above the damper are particularly dirty, the chimney sweep may clean those areas by hand.

A thorough inspection of the outside of the chimney is usually part of the service too, Cannady said. Many chimney-cleaning companies are also qualified to repair cracks or rebuild fireplaces and chimneys.

A chimney should be inspected after an earthquake to look for damage and when you first move into your home. “You never know what the previous owner burned in there,” Cannady warned.”

Up in Smoke

Burning anything other than well-aged and dried wood may cause a build up of creosote. Gas is the cleanest burning substance for a fireplace, but if yours is a wood-burner, make sure the wood has been dried for a long time, and choose wood that does not have a high oil content.

Some woods that are naturally high in oils, such as eucalyptus, can be burned if they have been left to dry for at least a year, said Lewis, who recommends buying wood from a tree service because they can tell you exactly what the wood is and how long it has been aged.

Plywood is a dangerous fireplace fuel, Cannady said, because it burns too fast and hot.

“A fire that burns too slowly or too quickly can be a problem. A fire that burns too slowly allows smoke to cool as it goes up the flue and turn into sticky tar clinging to the inside of the chimney, which could lead to a fire. A fast-burning fire sends up too many embers, which could start a roof fire.”

Never burn trash or any other paper products in the fireplace, especially Christmas wrapping paper. Glossy paper, such as wrapping paper, adds to creosote build-up. Paper is also lightweight, and even a small piece can float up the flue and start a roof fire, Cannady said.

Newspaper is fine for kindling as long as single sheets are rolled into tight balls placed under the wood grate.

Up on the Roof

Besides keeping the home fires burning safely, it’s important you keep the roof safe from sparks by installing a spark arrester or chimney cap.

A spark arrester is a screen that snugly covers the opening of the chimney. A chimney cap looks more like a little cage atop the chimney. The cap adds the protection of keeping out rain, which can collect on the smoke shelf and over time, erode it, according to Lewis.

The front of the fireplace should be covered with a well-fitted screen or glass doors.

“It doesn’t cost much to keep a chimney working well,” said Lewis. “But the cost of not keeping it in good shape can be very high.”

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The Hearth of the Matter

Chimneys are more complex that they appear. A guide to the parts:

Flue--Usually a large-diameter terra-cotta pipe.

Smoke chamber--Funnels smoke and gas into the flue.

Smoke shelf--Bounces stray downdrafts back up the chimney before they can blow the smoke into the room.

Damper--A steel or cast-iron door that opens and closes the throat.

Lintel--Heavy steel brace that supports the masonry above the fireplace opening.

Face--The masonry surrounding the fireplace opening.

Firebox--The chamber where the fire is built.

Hearth--Inner hearth holds the burning fuel. The outer hearth protects the house flooring.

Throat--Slot-like opening above the firebox that passes flames, smoke and gasses into the smoke chamber.

Source: Chimmney Safety Institute of America