Welcome to another edition of Office Acoustics 101. Last time we talked about Taming Office Noise in an open office environment. Today we’ll tackle the subject of drop tile ceilings and how they relate to several office related noise problems. While this article is geared towards office applications, please note that many of these principles can also be applied to school classrooms, commercial spaces, and residential applications. Drop tile ceilings are one of the most common sights you will see in a typical office setting. Drop ceilings are essentially a secondary ceiling that is installed beneath the main, structural ceiling. They are also sometimes referred to as suspended ceilings, t-bar ceilings, false ceilings, and grid ceilings, to name just a few. They are usually installed in order to hide the framework make-up of the building structure including wiring, piping, and duct work. They are also commonly used to house fire sprinklers and fire suppression systems. This allows for the tiles to be easily replaced in case of fire or other building damage. While there are many decorative tiles available on the market these days, most offices seem to use the same plain white industrial ceiling tiles that are readily available from most building supply stores. The problem with these tiles are that they are very thin, and although they are sometimes referred to as “acoustic ceiling tiles”, they are in reality very far from it, and basically just allow for sound to pass through them uninhibited. This can cause a number of different problems which I will outline below, along with resolutions to treat them effectively.
Sound Transmission Between Rooms
In many office environments, the shared walls between offices and conference rooms do not extend all the way to the structural ceiling deck, but rather ends where the drop ceiling grid begins. This can allow for sound to flank between the two spaces so that the person(s) in each office hears the other loud and clear whenever they are talking, typing, etc. (Ex. 1). This can be a big nuisance to the workers in each space, especially if your neighbor tends to be a loud talker!
Thankfully, there are a couple of ways that you can fix this. In order to block the sound from going up above the tiles and over into the adjoining room you have to install a barrier material in the drop ceiling. This can be done by inserting a Drop Tile Ceiling Barrier above the existing tiles or by replacing the existing tiles with a tile that has a barrier material already on it (Ex. 2). Our Signature Barrier Ceiling Tiles are a good example of this.
Both of these materials contain a layer of Mass Loaded Vinyl Barrier (a heavy, dense material used to block sound) to help stop noise from traveling up and over into the room next door. In order for this treatment to work effectively, you do have to completely cover the entire ceiling of at least one of rooms though. Partial treatment will still allow for sound to move through the untreated area.
Office and Conference Room Echo
Offices and conference rooms with lots of hard surfaces and high ceilings often have echo and speech intelligibility problems. As is the case with sound flanking between rooms, standard ceiling tiles do not usually have very good absorptive qualities either. As mentioned previously, sound tends to pass through them which allows for it to hit the ceiling deck and bounce back down. This can wreak havoc in rooms where speech intelligibility is of high importance (Ex. 3). No one wants to be on a conference call where they cannot decipher what the person on the other line is saying and vice versa. While we almost always recommend absorptive wall panels in this type of situation, sometimes the make-up of the room does not allow for that type of treatment (lack of wall space, walls made from glass, etc.). Installing specialty absorptive ceiling tiles designed for acoustics can be a big help in this situation. These tiles use thicker materials (usually compressed fiberglass or melamine foam) to help dampen and reduce the amount of noise that can bounce around the room.
Absorptive ceiling tiles come in many different styles and can have various facings to match the room’s decor. Examples include fabric-faced tiles, patterned foam tiles, metal-faced tiles, and wood-faced tiles. Certain tiles can even offer thermal benefits in addition to acoustic and these tiles also work well in open office areas, call centers, etc.