General
Information What
is a Controlled Environment Room (CER)?
Temperature
& humidity control/uniformity What
are temperature control and humidity control? What
are temperature uniformity and humidity uniformity?
What
are appropriate control and uniformity levels in a CER?
What
are the available methods to control or limit relative humidity (RH) in CERs?
Insulated
structure
How important is insulation R-value to controlled environment room operation?
What
is the standard insulated panel width and height?
What is the maximum ceiling panel span that does not require additional support?
What
are the perimeter space requirements for installing a CER?
What
is the typical thick nesses for insulated floor panels?
Refrigeration
equipment
Where
can the condensing units be located?
How
far from the CER can condensing unit be located?
Miscellaneous What
are power requirements for CERs?
What
are typical plumbing requirements for a CER?
What
is CTI's Emergency Response Program? General
Information What
is a Controlled Environment Room (CER)? A Controlled Environment Room is an enclosed area that is isolated to an appropriate degree from the surrounding space and provided with a means of regulating that enclosed space independent from the building mechanical system. Very basically, it is an insulated area that needs to be warmer, cooler, or more or less humid than its surrounding space. In most cases the needed conditions cannot be attained with the building mechanical system, requiring a separate, self-contained temperature and humidity control system.
Temperature
& humidity control/uniformity What
are temperature control and humidity control? When used to describe CER performance, control is the absolute value of the difference between the highest and the lowest temperature or humidity readings at a single location over a specified time period. Control requirements generally do not apply during defrost cycles, if the CER has a defrost system.
What
are temperature uniformity and humidity uniformity? When used to describe CER performance, uniformity is the absolute value of the difference between the highest and the lowest temperature or humidity measured at numerous locations at a single point in time. Uniformity requirements generally do not apply during defrost cycles.
What
are appropriate control and uniformity levels in a CER?
Temperature control and uniformity levels of 1°C are very common and easily obtainable by Climate Technologies equipment and systems. Temperature control and uniformity levels of 0.5°C are also common, but reflect a greater level of process control. Climate Technologies also routinely provides this level of control. Your control requirements should be determined by your application, not by what equipment is available.
Relative humidity control and uniformity levels of 5% are very common and easily obtainable with Climate Technologies equipment and systems. Humidity control and uniformity levels of 3% are also common and reflect a greater level of process control. This advanced level of control is also available with Climate Technologies standard equipment offering.
What
are the available methods to control or limit relative humidity (RH) in CERs?
Relative humidity is controlled by adding or removing moisture from the air in the controlled space. The addition of moisture, called humidification, can be accomplished in several ways, including atomization of liquid water, steam introduction, pressurized spraying of water, and ultrasonic atomization of liquid water. The removal of moisture, called dehumidification, can be accomplished by condensing moisture on a cold surface or adsorbing it in the vapor state with a desiccant. Each method has particular aspects which may make it more suitable to a particular application. A Climate Technologies specialist can help you evaluate various options and make an informed selection.
Insulated
structure How important is insulation R-value to controlled environment room operation?
Most insulated panel manufacturers are producing urethane foam panels with R-values of 28 to 30 with current technology. This is suitable for a wide variety of applications. In some cases, lower temperature rooms will require higher insulating values available with increased panel thickness. The difference in controlled environment room operating cost between an installation with R-28 and one with R-30 is so small it should not be a consideration. You can get more information regarding insulation and applications from your Climate Technologies representative.
What
is the standard insulated panel width and height? The most common width of an insulated panel is 46" with standard sizes available in multiples of 11.5" (11.5", 23", 34.5" and 46") and 12" standard corner sections. Custom panel widths are available with the customer simply being charged for the next largest panel width (42" panel would cost the same as a 46" panel). Standard exterior room heights start 7'6" and extend upward in one foot increments for rooms with 4" thick floors. Reduction of the floor thickness or deletion of the insulated floor panels reduces this dimension directly.
What is the maximum ceiling panel span that does not require additional support?
Generally, limiting either the length or width on the room to no greater than 13’-6” eliminates the need for additional ceiling panel support. There are special cases where longer spans are suitable without exterior support. When exterior support is needed, it will be either suspension from the building structure, interior post and beam, or external self-supporting steel. Each method has elements which may make it more suitable to your project, so consider all available methods to make an informed selection. What
are the perimeter space requirements for installing a CER? In order to inhibit condensate from forming on the exterior of a Cold Room, a 2" air gap is recommended around the perimeter of the CER. Rooms operating at colder temperatures, or in warm humid environments, may require more space.
To facilitate proper room assembly, an 8" clearance is required above the CER. This clearance may be reduced with special installation techniques that will result in a more costly installation. To facilitate maintenance of any refrigeration equipment installed on top of the CER, a 36" minimum clearance should be provided for maintenance personnel.
What
is the typical thickness for insulated floor panels?
Standard floor panels are 4" thick. Optional 2" floor panels reduce access ramp length or depressed slab depth. Note that reducing the insulated panel thickness directly reduces the insulating value. In some cases, reduced profile panels are not suitable, so check your application with a Climate Technologies design specialist. A limited range of applications may not require any insulated floor panels. These applications should be carefully considered with a design professional to assess the long term impact of an un insulated floor.
Refrigeration
equipment Where
can the condensing units be located?
Condensing Units are either remotely located away from the CER, or mounted on top of the insulated structure. Remotely locate units can be indoors or outdoors. The location chosen for a condensing unit should accommodate considerations of heat rejection, noise, vibration, visibility, safety, and accessibility for maintenance.
How
far from the CER can condensing unit be located?
Our usual recommendation is for the maximum refrigeration piping distance to be 75 feet with a maximum 35 foot elevation change. We have installed many systems exceeding these
distances/elevations which have been designed to meet the CER's specific needs and are operating properly. CTI is able to design longer refrigeration runs. It is important to make sure such requirements are clearly noted during preliminary design stage.
Miscellaneous What
are power requirements for CERs?
A typical CER will require two (2) electrical circuits. One circuit is for the Control Panel (CP) and another circuit is for the condensing unit. Generally, these circuits will be 120-208/60/3, 4-wire for the control panel and either 208 or 460 volt, three phase for the condensing unit. The final voltage selection can be limited by the availability of machinery in a particular application range with the desired electrical characteristics.
What
are typical plumbing requirements for a CER?
Controlled environment rooms with refrigeration systems will require a condensate drain. This is typically accomplished with a gravity induced flow to an open site drain near the room, though other arrangements are possible. Rooms employing certain types of humidification equipment require water supply and drain. The water supply may sometimes be from a source other than the potable water supply.
What
is CTI's Emergency Response Program? CTI provides a 24/7/365 Emergency Response Program to support our customers. The customer is provided with a telephone number to contact CTI. A trained and experienced CTI employee will respond quickly to provide support and initiate a service call (if necessary). This program is tested occasionally for robustness and typical response times have been less than 15 minutes. |
