Minimize noise and odor

By Mark R. Hafen, AIA

When people shop for used cars, they kick the tires and check under the hood. When they shop for veterinary services, the evaluation is more subtle. But in both cases, they form lasting opinions based on first impressions. That's why it's critical to minimize noise and odor. Simply put, if your clinic stinks, clients may worry that your medical care stinks, too.

Besides making a better impression with clients, controlling odor and noise makes your hospital a nicer place to work. After all, if you can't hear yourself think, how can you do your best work? Use these tips to take control before noise and odor drive clients and team members away.

Controlling noise

Between barking dogs, meowing cats, and busy staff members, you may wonder what peace and quiet sounds like. Well, you can't eliminate noise, but you can contain it and prevent it from spreading through the hospital with these strategies:

Suck up the sound. You can keep noise from bouncing off walls and sticking around by installing noise-absorbing materials. So, whether you're building a new hospital or looking for ways to quiet your kennel, ask your architect, contractor, or building supply store personnel to help you choose products with a high noise reduction coefficient (NRC) rating.

The NRC numbers are based on lab tests that determine how much sound the material absorbs. For example, a ceiling tile with an NRC of .65 absorbs 65 percent of the reverberant noise that hits the tile; an NRC of 1.0 means the tile absorbs all reverberant noise.

To minimize noise from the runs, install as much sound-absorbing material as possible in your kennel. I recommend this approach: Use a perforated mylar-faced acoustic ceiling tile with an NRC of .65; hang mylar-faced sound baffles with an NRC of 1.0 from the ceiling; and place sound-absorbing, fabric-wrapped wall panels with an NRC of .85 to 1.0 on the wall. These materials absorb sound well, but they're not durable or easy to clean, so install them where they're least likely to get wet or damaged.

Build a better wall. Absorption keeps sound from bouncing off the walls and adding to the din, but you still need to contain the initial bark, squeal, or yell. That's where you rely on solid walls and doors.

Architects and builders use sound transmission coefficient (STC) ratings to describe how much noise a material screens out. For example, a wall with an STC of 45 stops about 45 decibels of sound, or the equivalent of a normal speaking voice. To give some perspective, a dog bark generates 100 or more decibels. It's not practical to build a wall that screens out all of that noise. Fortunately, it's also not necessary.

A wall with an STC of 55 to 65 works fine for a kennel because normal background noise masks the 35 decibels of sound that escapes. Just make sure your sound-isolation wall extends to the roof deck to stop noise from traveling up and over.

To see how your wall rates, check out these numbers:

2-by-4 stud wall with drywall on both sides: STC of 35

2-by-6 stud wall with staggered studs and two layers of drywall on each side: STC of 58

8-inch-thick concrete block wall with the voids filled: STC of 55.

Also consider how a window will affect your wall's sound blocking power. A 1/8-inch-thick piece of glass has an STC of just 25. And a 2-inch-square opening completely negates the sound isolation capabilities of the wall! If you want a window in a sound-blocking wall, use two layers of glass separated by a 2-inch air space to get an STC of about 45.

The type of door you install also makes a difference. For example, a typical hollow-core wood door offers an STC of 35, while a typical solid-core wood or hollow metal door boasts an STC of 45. Again, a gap will let sound pass right through, so be sure to install stripping around the door.

Finally, try to take advantage of the background noise in the rest of your practice. For example, if you're building a new hospital, place the runs near busy medical areas' and not next to the doctors' office or a consultation room.

Raise the roof. Outside, with no walls to stop it, sound drops off dramatically with distance. It's virtually impossible to create a room big enough for sound to die off naturally, but increasing the height of ceilings in kennel and ward spaces to 10 feet or higher helps minimize sound bouncing off the ceiling and gives you more room to install absorbent wall and ceiling panels and baffles.

Cover it up. When you've absorbed and isolated as much noise as possible, add background noise. And don't think covering up the problem means you failed to resolve it. After all, noise isn't a problem unless it's perceived as one. Think of it this way: It's hard to hear a dog barking if you're standing next to a runway.

Another benefit of installing a sound system: Studies show that easy-listening and instrumental music actually calms animals in holding areas. So you'll soothe clients and their pets--and give yourself a break from the sound of barking dogs.

Block off hidden passages. You may not think of your air ducts as noise conductors--but they are. Fortunately, heating and ventilation zones often coincide with sound-control zones, so you can usually eliminate ducts that pass from noisy areas to quiet ones. When you can't, consider installing a sound attenuator in the duct, and seal the joint between the wall and the attenuator. Or line the duct with acoustical lead to contain the sound.

Controlling odor

Uncontrolled noise makes your ears ring, but unpleasant odors can make your eyes water or your stomach roll--which may be even worse. It's certainly not nice to visit or work in a place that offends your nose, so try these tips to resolve any odor issues:

Eliminate the source. Frequent cleaning of runs and cages is the most obvious step. Place water hose bibs in convenient locations, and use high-pressure, hot-water spray and disinfectant systems to wash away waste and bacteria that cause odors. A well-designed, adequately sized floor-drain system also facilitates waste removal.

Unfortunately, many areas produce odor regardless of how clean you keep them--think of the tub your team uses for medicinal dips or the fecal sink in the lab. In these cases, you need to focus on keeping the unpleasant odor from spreading.

Keep clean air flowing. Odors travel through the air, so adjusting air supply and exhaust controls most odors. In older facilities, it's common to find little or no fresh air coming into the clinic for the sake of smaller utility bills. This approach compounds odor problems by sucking smelly air back into the system and pumping it into other rooms.

Ideally, your heating, ventilation, and air conditioning (HVAC) system should provide six to 10 air changes per hour--and more in some critical areas. This means that the air in a room will be replaced completely every six to 10 minutes. You also need to make sure you've installed enough exhaust fans. I recommend the following air changes:

Runs and dog wards: 12 air changes per hour, with a minimum exhaust fan capacity of 500 cubic feet per minute (CFM) and enough fans to provide 50 CFM per dog

Cat wards: Eight air changes per hour, with a minimum fan capacity of 200 CFM and enough fans to provide eight CFM per cat

Grooming: Eight air changes per hour, with a multi-speed exhaust fan that offers at least 300 CFM

Treatment and medical areas: 10 air changes per hour, with a minimum exhaust fan capacity of 300 CFM

Office/reception areas: 25 percent to 50 percent of return air should be fresh, outside air

Isolation: Eight air changes per hour, with a minimum exhaust fan capacity of 200 CFM

Lab: A range hood with a 150 CFM fan over the sink eliminates odors effectively, especially for fecals

Exam rooms, bathrooms, and dark room: Exhaust when needed with a standard 90 CFM fan.

Develop a multi-zone system. In a multi-zone system, you group rooms with similar heating and cooling requirements or odor-producing potential and give them separate HVAC units. For example, you might keep wards, kennels, grooming, and bathing areas in one zone and put a doctors' office, the reception area, and exam rooms in another.

The zone system lets you provide different amounts of fresh air depending on need and keeps odors from spreading between zones. Just make sure the return air for one zone doesn't draw from an adjacent zone.

Create areas of positive and negative pressure. To create negative pressure in a room, you exhaust more air than you supply. To create positive pressure, supply more than you exhaust. Negatively pressured rooms hold odors inside, and positively pressured rooms discourage entry of air and odors. For example, if you create positive pressure in the reception area, you'll keep odors from migrating from the back of the clinic. If you create negative pressure in the ward and kennel, you'll draw clean air from the rest of the clinic.

Positive pressure also helps control germs and contaminants. For example, pumping more air into surgery than you return keeps germs from entering; exhausting more air than you return from the isolation ward helps minimize the spread of contaminants.

When it comes to noise and odor, your best bet is to avoid problems. But you definitely need to do what it takes to fix any chronic problems. You'll improve clients' experiences and team members? workplace.

Mark R. Hafen, AIA, NCARB, is a Veterinary Economics Editorial Advisory Board member and a senior partner with Gates Hafen Cochrane Architects PC, an architectural firm in Boulder, Colo., that focuses exclusively on designing veterinary facilities. You can reach him at (303) 444-4413 or ghc@ghcarch.com.

August 2000 Veterinary Economics