MRI Cooling Units

(c) The air distribution ductwork shall be constructed of either PVC or

aluminum to maintain the integrity of the magnetic field.

3.17.2.2 COMPUTER COOLING UNITS: This unit is required for the High-field

system only. The specific requirements are:

(a) The air supply outlets shall be located at the floor level with the

air directed toward the cabinet inlets. The return air inlets shall be

located at the ceiling level, above the cabinets, and near equipment

(b) The physical location of the cooling unit should be coordinated with

the magnetic field line and should be away from the 10 guess (unit for

magnetic field intensity) line.

(c) The supply air entering the computer room shall be at 18 degrees C (65

degrees F) dry-bulb temperature and 60 percent RH maximum.

3.17.2.3 MRI COOLING UNITS: To cool the MRI and control equipment, a

dedicated, closed-loop water-cooling equipment shall be provided. The

equipment shall comprise of a dedicated air-cooled, chiller, circulating

pump and interconnecting piping. See Paragraph 2.12.9 for the dedicated

refrigeration unit. Other specific requirements are:

(a) The pH level, total solid content, total hardness, and alkalinity of

the circulating water shall be within the limits prescribed by the

equipment manufacturer.

(b) The limits of the inlet water temperature, pressure drop through the

equipment, and maximum inlet water pressure shall be in accordance with

the equipment manufacturer's recommendations.

(c) The water piping design shall meet the "Radio Frequency" requirements.

The piping laid in walls and chases shall be provided with clearly marked

and identified access doors for servicing valves and other piping

specialties.

(d) While the environmental and computer air handling units shall be

connected to the building central chilled water system, for back-up, the

capacity of the dedicated air-cooled water chiller shall also include the

cooling loads of the environmental air handling unit and computer room

cooling unit. The selection of the leaving chilled water temperature

shall, therefore, be such that the requirements of entering water

temperature to the water cooled equipment and the supply air temperatures

of the air cooling units are simultaneously satisfied.

3.17.2.4 ALARMS:

(a) Ambient Temperature Alarm: Provide a high temperature alarm local and

at the ECC, if available, for the temperature sensor. The sensor is to be

located near the top rear of the computer cabinets. The sensor will be

supplied by the MRI equipment manufacturer.

(b) Water Alarm: Provide water sensor alarms (local and the ECC, if

available) on the raised deck and under the raised flooring. It shall

close and sound the alarm upon detection of moisture water supply to the

equipment.

HVAC DESIGN MANUAL

3-19

HVAC REQUIREMENTS FOR OCCUPIED AREAS