Cleaning Laundry Ducts

The hospital’s dryers could hardly dry the clothes anymore and the lint buildup was so bad that the fire inspector had cited the place.”

So begins the story by one of Action Duct Cleaning’s technicians of a Los Angeles medical centre that was experiencing the “laundry list” of symptoms that occur when a laundry exhaust system is not maintained.

Every commercial laundry has a duct or series of ducts – the exhaust system – that remove the hot, moisture-laden air from dryers and exhausts it outdoors on the roof or via an outside wall.

This hot air is filled with lint particles that, over time, deposit inside the duct. Lint can stack up until it is inches thick. Regular maintenance is needed to remove the accumulation. Maintenance is commonly done every three to six months but may be needed as often as monthly. When maintenance is ignored, the lint buildup – which can eventually occupy 50-75% of the duct – can cause a lot of problems.

The common signs that a laundry exhaust needs cleaning include:

• Clothes taking too long to dry
• Excess lint buildup in the ducts, causing a fire hazard
• Dryer units automatically turning off because the heat is not exhausting
• Malfunctioning of fire dampers in the ducts
• Higher concentrations of lint in the indoor air
• Rusting of the ducts from holding wet lint for long periods

Of all these factors, fire is by far the number one concern. Lint is highly flammable. The lint buildup not only creates a fire hazard, but it inhibits fusible (low melting point) links on the fire dampers inside the duct that are supposed to close during a fire to prevent the flames from spreading. If the links are coated with lint, they may not be able to melt at the proper temperature. So the fire damper may not close.

Air quality is another issue. The excess lint gets into the air because the exhaust can’t take it out. So, the lint gets into the heating and air conditioning system.

If the flow through the vents is not right, the back pressure can trip a relay switch and shut the dryer off.

For hotels and similar facilities, customer service can be directly affected by the lack of laundry exhaust cleaning. Slowed drying times means towels and sheets not getting to the rooms on time, particularly when the house is full.

Local fire inspectors may show up at random to look at a laundry exhaust. Fire codes, both regional and national, are clear that regular maintenance needs to be done. The National Fire Protection Association, the leading voice in American fire codes, states in section 91-9.3.4 of their manual, “Accumulations of conveyed materials and residues shall be removed from…ducts…and air-moving devices.”

Another problem that comes up is lint accumulation getting so thick in the ducts that it blows onto the roof, creating an unsightly mess. Or, some ducts have a “bird screen” at the end to prevent animals from entering and this screen can clog with lint, reducing air flow.

Cleaning laundry ducts requires openings in the ducts so that lint can be removed (sometimes by crawling the ducts). Even though building codes require that most laundry ducts be initially installed with such “access doors,” occasionally one or a few may need to be added so a thorough cleaning can be done. (We have found that those who install the ducts do not necessarily know how much access is required for proper cleaning).

We have learnt in our more than 30 years in the business that most laundry maintenance professionals are educated about the need for laundry duct cleaning. A few, however, learn through a “baptism of fire.” Our senior account executive said once, “I recall a woman who had worked at a top hospital in the Los Angeles area that had a laundry duct fire. She now worked at a hotel and, believe me, she was insistent about having us clean the dryer duct on time.”

In summary, there are plenty of good reasons for maintaining the exhaust systems in a commercial laundry setting. A regular cleaning schedule is part of any recipe for a smooth-running operation.