August 2007

Keeping It Safe

by Robert Tutterow

Keep It Clean By Removing Exhaust

The best way to keep your station and, more importantly your lungs, clean is by installing and using diesel exhaust removal systems. Many stations already have a system, but far too many are still without. There are three methods of removing exhaust from a station that will be reviewed later.

Before we talk about how to resolve the problem, let’s talk about the hazards of diesel exhaust, which have been documented in many studies. The hazard is particularly acute during engine start up.

I remember the first diesel engine my volunteer department purchased in 1980. On a cold winter evening, that Caterpillar 3208 would puke exhaust emissions like a locomotive during the early years of the railroad. We were in an immediately dangerous to life or health (IDLH) situation before we even left the station.

At that time, the dangers of diesel exhaust had not been documented, and there were no diesel exhaust removal systems being marketed to the fire station. We actually constructed a wooden, stand-alone frame to hold a household furnace filter and placed the filter at the exhaust tailpipe in an attempt to capture some of the particulates.

In addition to the visible particulates, there are other harmful gases in diesel exhaust, including the odorless killer, carbon monoxide, nitrogen oxide, sulfur dioxide and a host of volatile organic chemicals – all bad stuff to be breathing in. It is documented that diesel exhaust is a likely human carcinogen.

Enough Contaminants

In addition to the air-borne hazards, the accumulation of particulates on the interior surfaces of the fire station poses a risk through absorption and ingestion. Firefighters are exposed to enough contaminants through their on-scene activities, as well as from exposure to unclean personal protective equipment (PPE).

So, keeping the station free of these contaminants is a no-brainer. A diesel exhaust removal system should be standard equipment for any new station. They should be added to existing stations, and the current fire grant program accepts applications for such systems.

As mentioned earlier, there are three types of diesel exhaust systems in use today. These are: source capture station mounted; source capture truck mounted; and air filtration units mounted in
the station.

The term “source capture” is used by the manufacturers of systems that capture the contaminants before they are exhausted into the station. Keep in mind that all the manufacturers will provide documentation that their system meets all applicable standards for diesel exhaust removal. Each system has its benefits and features.

Station-mounted source capture systems are typically the type that have hoses connected directly to the exhaust tailpipes with blowers used to capture and exhaust the contaminants to the outside before they enter the station.

There are several manufacturers of these type systems and most hang their hoses on a rail from the ceiling area of the station. One manufacturer offers a system that is mounted on the apparatus floor. When used correctly, these are very effective in removing contaminants.

The Breakaway Feature

When considering this type of system, keep a few things in mind. Evaluate the effectiveness of the seal of the system to the exhaust pipe. It should not leak. Examine the breakaway feature of the system and learn how much will break away and how difficult the repair will be in the event of a mishap. It’s important to know whether there is a local dealer who can perform the repairs quickly.

As mentioned earlier, the effectiveness of these systems is excellent if used properly. They will remove almost 100 percent of contaminants. If not used properly, they are not as effective. Proper use is pretty simple – just connect the hose to the apparatus when it is in the station. But therein, is the biggest downfall of these systems – firefighters must make the connection and use them to have any benefit at all. That problem should be easily resolved when the firefighters realize the benefit of the investment in the equipment.

Source Mounted Systems

Vehicle source-mounted systems are connected to apparatus exhaust systems and capture the contaminants before they are exhausted. This is typically done by use of a ceramic filter. The system is designed to be automatic as it is activated when the engine starts and remains activated for a pre-determined length of time to allow the apparatus to exit the station.

The system then deactivates and the contaminants are exhausted into the atmosphere. The system is also activated when the apparatus is placed in reverse (backing into the station) and can be manually activated if diesel exhaust is a concern at an emergency scene.

These systems are effective in that firefighters do not have to connect the system to the apparatus. They are also nice in that they are completely hidden. They mount under the apparatus without using compartment space. A key consideration here is every truck in the station needs one to be effective.

It’s important to note that stations outlast trucks and every new truck will need a new exhaust capturing system. Also, the ceramic filter will need to be replaced on occasion. A busy metro department can expect to replace the filters at least once a year.

Departments with fewer runs will have longer filter life expectancy.

The effectiveness of the contaminant system is not quite as good as the station-mounted source capture as some exhaust is discharged in the station. However, the exhaust meets the safety standards.

Air Filtration Units

A key consideration with this system is the cost is for all apparatus, including costs for replacement filters.

There are also the air filtration units to consider. These are typically ceiling-mounted units containing powerful blowers to take the contaminated air from the apparatus bay into its filtration system.

Because of the sophisticated air filtration systems, these are far different than a simple “attic fan” mounted in an exterior wall of a fire station. They are designed to be automatically activated such as when an apparatus bay door is opened and then shut off automatically after a pre-determined amount of time. These systems require no firefighter intervention, and that is one of their key selling points.

In addition, one system will usually work for all the bays. The downside of the system is that it does not capture all of the particulates at the source. It captures the contaminants after they are discharged into the apparatus bay. Yet, as stated before, most of the manufacturers have documentation that supports their effectiveness to applicable standards. Because of the filtration system, there is the consideration of the frequency and cost to replace filters as they become dirty. And it’s important to consider the effectiveness of the system for all the vehicles in your bay.

If fire station issues such as equipment and design are on your radar, please be sure to attend the Fire Industry Equipment Research Organization (F.I.E.R.O.) Fire Station Design Symposium in Charlotte, N.C., on Oct. 25-27. For information, see www.fierofirestation.com.

Editor’s Note: Robert Tutterow, who has 30 years in the fire service, is the Charlotte (N.C.) Fire Department health and safety officer. He is the chair of the National Fire Protection Association (NFPA) Fire Department Apparatus Committee’s Safety Task Force Group and is on two other NFPA committees, the Structural and Proximity Firefighting Protective Ensemble Technical Committee and the Technical Correlating Committee for Fire and Emergency Services PPE.

Station-mounted source capture systems typically have hoses connected directly to the exhaust tailpipes with blowers and duct work overhead to capture and exhaust the diesel engine contaminants to the outside.