The ceiling is an often-overlooked surface in the cleaning environment primarily because of the perception that ceilings are too difficult or impossible to clean.  Some building managers feel that simply painting the ceiling is faster and easier than any cleaning process.  A basic understanding of ceiling surfaces is critical for deciding the best technique for restoring the "clean" look to the surface. Most ceilings fall into one of several categories.

Acoustical (acoustic) - This ceiling type is the most common found in commercial buildings and in most office areas.  It is porous and basically appears smooth with small pinholes and crevices.  The primary function of all acoustical tile is for sound control.  There are, however, many types of acoustical tile, each with unique functions.

• Standard system - This acoustical tile is used for noise absorption and as a decorative overhead surface.  The standard system tile is made of wood fiber, mineral fiber or metal pan.  This ceiling is stapled, cemented or suspended in metal framework to the existing ceiling structure.  Wood fiber tiles will absorb between 45% and 65% of the sound, which strikes their surface, mineral fiber ceilings, 55% to 80% and metal pan (perforated aluminum or steel below a mineral pad) 80% to 90%.

• Time design rated system - This system is used as a fire protective barrier for structural steel building components.  They are always made of incombustible mineral fiber and are usually of denser composition than standard acoustical material.  This ceiling tends to

require less cleaning since it does not allow the passage of dirt-laden air to pass through it, as do standard tiles.  Time design tiles are the only acoustical ceiling tiles, which can be painted with no effect on their acoustical or fire protective performance.

• Ventilation system - This system is designed to distribute conditioned air (heating and cooling).  The entire ceiling delivers this conditioned air via perforations, which run through the entire thickness of the tile.  This conditioned air is fed continuously into a sealed area above the ceiling called the plenum where it builds up in pressure.  This pressure forces the air into the room through the ceiling perforations.  Ductwork and vents are not required with this system, there are no cold spots as can be found in ductwork vent systems.  The constant downward flow keeps dust and dirt from accumulating on the ceiling surface.  The low rate of air movement also keeps dust and dirt from circulating around the room.  Any broken or cracked tiles should be replaced since they reduce the plenum pressure, which affects the uniformity of air distribution.

• Ceramic system - This system is used in locations, which are exposed to high moisture conditions.  These areas include indoor swimming pools, food processing facilities, outdoor amphitheaters, and parking garage s. These ceiling tiles are composed of an inert composition which will not expand, contract or weaken under prolonged exposure to moisture.

• Multi-functional integrated system - This system combines into a single assembly all the necessary provisions for room lighting, air distribution, and acoustical control.  All components - mechanical, electrical, and structural - are blended together to create a unified visual effect.  This design reduces above ceiling congestion.

• Special purpose systems - There are a few specialized types of ceilings, which have been designed to meet the requirements of unique environmental conditions.  The hospital is an example of one of these locations where unique conditions exist.  In many parts of a hospital, the interior surfaces must be scrubbed and disinfected on a weekly basis or even more often to discourage the growth of bacteria. Except for ceramic ceilings, traditional acoustical ceiling tiles cannot withstand the moisture and scrubbing necessary in this environment. 

Two ceiling systems have been designed to meet the cleaning requirements of this type of environment.  The first system is a standard acoustical tile, which has a Mylar membrane covering the tile, but attached only to the outer edges.  The face of the tile is free to vibrate.  When a sound strikes the surface it passes through the Mylar and is absorbed by the tile.  The membrane allows for repeated wet cleanings. It should not be painted.

The other specialized system in this environment is “self-sanitizing," which relies on a chemical substance in the tile, which destroys bacteria.  This system does not require wet cleaning to control bacterial growth.  It does, however require periodic vacuuming to remove dust, which can harbor bacteria.  This tile should not be painted, since this would destroy the bacteria resistance.

Glacier - This ceiling is constructed of acoustical ceiling material. However, it looks much like icicles. Glacier ceilings must be sprayed with ceiling cleaning solution from four different directions to assure complete coverage of the surface. 

Popcorn - This ceiling is sprayed onto a previously existing non-acoustical type ceiling already in existence.  The result is a stucco-like surface.  The disadvantage of this system is that if a stain occurs, there is no tile to replace it.

Burlap - Burlap is very similar to acoustical ceilings.  However, it has a greater tendency to absorb dirt directly into the fiber making it difficult to clean the tiles with one cleaning.

Vinyl-wrapped sheetrock - This is normal sheetrock or wallboard painted with enamel, latex or flat paint.  The enamel and latex paints allow the spray/wipe technique to be used.  Flat paint ceilings should be repainted when they become soiled since the flat paint can be removed with mild agitation or detergents.

Ceiling Cleaning Procedures – For non-porous tiles a vertical process of wall washing can be used.  For porous tiles a specialized enzyme/detergent based chemical is sprayed onto the tiles with the use of a pressure sprayer that only reaches 200 – 300 psi, or by using a 2-gallon pump sprayer. This enzyme/detergent will break up complex dirt molecules and loosen them from the wall surface.  The "broken" dirt molecules later fall from the wall as dry soil and are cleaned up through normal vacuuming, dust mopping, and dusting procedures. 

•  Set up "Floor Caution" signs at entrances into area being cleaned.

•Cover all electronic equipment, fabrics that might "bleed," paper and other natural fabrics with paper/plastic drop cloths.  Keep the paper side facing upwards.  The paper prevents over-spray solution from running onto other surfaces. Items such as desks, tables, chairs, and other furniture need not be covered with drop cloths, however it is faster and more efficient to cover these items than it is to wipe over-spray off of them during the clean up procedure.

•  Prepare ceiling by removing dust, soot and carbon from the ceiling, air diffusers, lighting lens covers and speaker grills.  This is accomplished by vacuuming these areas.

•  Place the ceiling cleaning spray machine or the 2-gallon pump sprayer in the center of the room.  Fill a 5-gallon rinse bucket with warm.

•  Put on impermeable gloves, splash goggles, and place a paper respirator mask over your nose and mouth.  This will prevent over-spray mist from being inhaled.

•  The solution is shipped in 2 parts (activator and cleaner).  Follow directions EXACTLY or the enzyme/detergent process will not work. 

•  Place the mixed solution into either the ceiling cleaning spray machine or 2 gallon sprayer.

•  Perform the porous/non-porous test by spraying the solution onto the ceiling surface.  If the solution is absorbed by the surface, it is porous.  If the solution is not absorbed, it is non-porous.  Non-porous surfaces must be wiped dry while porous surfaces do not.

•  Begin the cleaning process by starting along the edges of the ceiling.  Avoid spraying solution on the wall.  A second crewmember can wipe excess solution from the wall area. This is performed by following the sprayer using a sponge held by a holding clamp on a 6-foot extension pole.  After the perimeter is completed, repeat this procedure towards the center of the room.