Soundproofing a Noisy MRI Scanner
L.B. Writes:
MRI scanner – magnet makes loud noises and bothers the technicians in the control room. Noise comes through RF door and wall.
L.B.,
I have a few products that will definitely help you and will go through the first few to get the ball rolling. At any point, if you have any questions or want to discuss the proposed product or products. I can’t remember the last time that I have been around an MRI so can not recall the exact noise that the machines made, but I assume that it is a very low mechanical “drone”. If this is the case, it is a fairly challenging acoustical situation.
I would first start by treating the door. Getting an air tight seal around the door is absolutely critical to blocking sound, so if there are any air gaps around the sides or between the door and the floor, they must be taken care of. This can be done with one of our adjustable door seals or by purchasing an acoustically rated door like the Studio 3D door. Clearly, the door seal kit is going to be more cost effective than purchasing a whole new door assembly, but depending on the severity of the problem, it may be needed.
The Door Seal Kits are clear anodized aluminum housings with black neoprene gaskets to make the seal. The jamb seal screws into the door jamb and covers the two sides as well as the top of the door. Each kit will have an automatic door bottom where a neoprene gasket is pushed to the ground as the door is closed. When the door opens, a spring inside of the housing pulls the neoprene back up into itself. There are two kits to choose from. The standard kit usually sells for around $177.00 and is best used with a hollow core door. The Heavy Duty kit sells for around $335.00 and is best used on a solid core door.
The Studio 3D door is a full replacement door. This is a seven layer door which we have designed specifically with soundproofing in mind. The door itself is 2 ¾” thick and is extremely heavy. We mortise a jamb seal as well as an automatic door bottom into the system so they can not be seen until the door is opened. Our standard doors have an STC (Sound Transmission Coefficient) of up to 56 which is incredibly good. The standard Studio 3D door usually sells for about $2,500.00 not including the installation kit ($29.99), a crating fee and shipping. This is clearly a lot more, but it is also a better performing system.
As far as treating the wall, there are many different ways to approach this. Ideally, if you have the ability to do any kind of construction (hanging a new layer of sheet rock) it will yield a better outcome, but that is not always possible. Assuming that you are not able to do that in this case, I would recommend a few different products. (If you ARE able to do some construction, please let me know as I will make some recommendations along those lines.)
My first recommendation would be the Melamine Composite panels. These are 2′ x 4′ panels made from standard melamine acoustical foam with a center layer of Mass Loaded Vinyl which is a noise barrier. These panels are about 1 3/8″ in overall thickness and will weigh about 9lbs each. Most times they are adhered directly to an existing sheet rock surface and must cover the entire surface to be able to do their job. The “active ingredient” in the product is the vinyl. This is a product that was designed to replace lead. Because of the mass and density of the vinyl, the sound has a lot more “stuff” to hit as it travels away from the noise source. As the sound wave hits the vinyl, because of it’s mass, the sound wave is converted into heat energy as the vinyl moves and vibrates. These panels will also absorb a significant amount of echo within the room so that the noise made by the machine does not echo around which is also important. These panels usually sell for around $11.00 per square foot.
Another option for acoustical treatment of the wall would be the Sound Silencer acoustical panels. These are also 2′ x 4′ panels that are generally glued to the sheet rock surface. They are available in a 1″ or 2″ thickness, and obviously, the thicker the better. They will not block as much sound or absorb as much echo as the Melamine composite panels but they are also more cost effective and will not hold an electromagnetic charge which may be critical in this type of application. The 1″ panels usually go for about $5.50 per square foot and the 2″ panels would be $7.50 per square foot.
Blocking sound is generally a fairly involved process that is definitely possible if it is done completely. It will always be true that the lower the frequency, the harder it will be to block the sound which is why I mentioned that if this is the case, it will be a tougher problem than if it were a machine that made a higher pitch sound. In some cases, however, all you can do is all you can do. If you have the ability to take a few digital pictures of the space and E-mail them to me, I would be happy to take a look and make some other recommendations, but rather than getting too in depth and confusing both of us, I will leave it at this for right now.
3 Comments
LS
I would advise against replacing the door to an MRI room with a soundproofing door.
An MRI machine needs to be insulated from radio waves, because it uses specific frequencies of radio waves to work. An MRI room–and the door to such a room–must have a layer of copper or steel called the RF shield to protect the machine from interference because of outsife radio waves.
Hanging acoustic foam and sealing doors are both good sugestions, but replacing the door to an MRI with some soundproof designed door is a bad idea, unless it can be proven that the door blocks also blocks radio frequencies.
Tammy
Ted: I work in a medical office building that has an MRI scanner in it. We are looking for ways to soundproof the noise from other areas of the building. A physical therapy office is on the opposite side of the MRI room. Our main focus at this time is to lessen the noise in there. We have recently hung a soundproofing product on the MRI wall, put the product between the 2 walls, and put the product on top of the MRI in the attic. It does not seem to have helped at all. Do you have any other suggestions? Thank you, Tammy
Ted W
Tammy, thanks for the comment.
Soundproofing is really something that needs to be done with the correct intent to be done at all. Could you send me a description of the building components that were used for the construction of the wall? (Example: 5/8″ sheetrock, 2×4 metal stud, standard fiberglass insulation, etc.) The ceiling type is also important, and whether the common wall between the therapy office and the MRI room goes from the floor to the roof deck or whether it stops above a dropped ceiling.
The “best” way to proceed is going to depend on the building components that you have. It will give me a better understanding of what kind of infrastructure you are working with.
Thanks,
Ted