A server room cooling scope chooses the system type (CRAC, CRAH or ductless), sets redundancy so one failure does not shut down IT, defines monitoring and alarms, specifies airflow containment and raised floor details, and states who responds when cooling fails. Small telecom closets often need only redundant ductless units, while larger rooms need precision cooling with planned maintenance access.
- Comfort cooling is the wrong tool for most IT spaces. It shuts off at night, mishandles humidity and is not designed for a constant heat load.
- Redundancy is a design choice with a scope line: how many units, what happens when one fails, and whether they rotate.
- Alarms only help if someone receives them. The scope should name who is notified and at what temperature.
- Containment and sealed openings often recover more cooling than adding capacity.
- Plan the maintenance interface in advance, because working on cooling equipment in a live IT space has its own rules.
Why the office thermostat is not enough
A server room produces heat all day, every day, regardless of the weather or the building's schedule. Comfort HVAC is designed for people: it cycles with occupancy, may be shut down on weekends and is sized to a different load profile. When an IT closet shares a rooftop unit with the office, the first warm weekend can turn into an equipment outage.
The scope for IT cooling should therefore begin by defining the load in kilowatts of IT equipment, the intended temperature range, the hours (continuous) and the consequences of loss. A branch office closet with a switch and a small rack is one project. A room holding a hundred racks is another. Most commercial buildings sit between them.
CRAC, CRAH or ductless: choosing the system
| System | How it works | Best fit | Scope notes |
|---|---|---|---|
| Ductless split (single or paired) | Wall or ceiling indoor unit with an outdoor condensing unit | Telecom closets, small server rooms, retrofit spaces | Refrigerant line set, condensate removal, low-ambient operation for continuous cooling |
| CRAC (computer room air conditioner) | Self-contained refrigerant unit with its own compressor, floor or ceiling supply | Mid-size rooms without chilled water | Floor space, condenser location, humidity control method |
| CRAH (computer room air handler) | Air handler fed by chilled water from a central plant | Larger rooms in buildings with a chiller plant | Chilled water capacity, valve control, piping and leak detection |
| In-row or rack cooling | Cooling placed close to the heat source | High-density racks | Chilled water or refrigerant piping to the row |
Chilled-water CRAH units depend on the plant behind them. If the building plant is shut down for maintenance, the server room goes with it unless the scope includes a standby source. See chiller replacement scope of work. For smaller rooms, ductless mini-split installation is often the practical answer, and the VRF and split systems service covers the equipment families.
Redundancy: what the scope should say
"Redundant" means nothing until it is defined. Spell it out.
- N+1: one more unit than the load requires, so any single unit can fail or be serviced while the others carry the room. For a small space, two ductless units each sized to carry the full load are a simple version.
- Rotation: units alternate lead and standby roles so both get run hours and a hidden failure shows up early.
- Separate power and refrigerant circuits: each unit on its own circuit, ideally from separate sources where the building allows. Electrical work belongs to a named licensed electrician. Davinci's scope is the cooling equipment and its controls.
- Automatic start of standby: the second unit starts on a temperature rise, not after someone notices.
- Condensate management: pumps and drain lines are often the first thing to fail. Provide a float switch and an alarm.
Redundancy that has never been tested is a hope. Write a failure test into the closeout: shut a unit off and watch the standby respond, with the room temperature recorded.
Containment, raised floor and airflow details
Most overheated server rooms are airflow problems wearing a capacity costume. Hot exhaust air recirculates to server intakes; cold air leaks through floor cutouts; cabinets are installed with open gaps. The cooling unit works hard and the room is still warm.
Items to write into the scope
- Hot aisle or cold aisle containment, with doors or curtains, and who supplies them.
- Blanking panels in racks and sealed cable openings.
- On a raised floor: plenum height, perforated tile placement, tile cutouts and any under-floor obstructions.
- Return air path to the cooling unit, particularly in rooms with drop ceilings.
- Humidity control: the target range and whether the system humidifies, dehumidifies or both. Overdoing this wastes energy and risks condensate problems.
- Water detection under the floor and near any chilled-water or condensate lines.
Monitoring, alarms and failure response
When the cooling stops, a small room can pass a safe limit quickly. The monitoring scope matters because it determines whether you find out in minutes or in the morning.
- Temperature sensors at rack intake height, not just at the unit return.
- Alarm setpoints in two tiers: a warning level and a critical level, with different recipients.
- Alarm delivery to people who can act: IT on-call, facilities, and the service contractor, with a backup path if the network itself is down.
- A defined response plan: who goes to the room, what they check first, when to start shedding load or opening doors, and when to call the contractor.
- Event records stored with the equipment in the DaVinci Portal, so repeated trips show up as a trend.
If the building already has automation, tie the cooling alarms into it. See building automation controls upgrade scope of work for how to write that connection.
The maintenance interface
Servicing a live IT room is different from servicing an office. Access may be badge-restricted. Technicians may need an escort. Certain actions, such as shutting down a unit, require advance approval from IT. A maintenance agreement should reflect all of this.
- Access procedure, escort and any security training required.
- Notice required before taking a cooling unit offline, and which hours are acceptable.
- Parts held or ordered in advance for critical components.
- Visit contents: filters, coils, condensate pumps, controls and alarm testing. Compare to rooftop unit PM visit checklist for the way to organize visit steps.
- A defined method for reporting findings to IT in plain language.
For recurring coverage, our maintenance plans can include IT cooling equipment on a set schedule, and the diagnostics guide explains how we look for the cause of repeated trips.
Sample scope language
Contractor shall furnish and install two cooling units, each capable of carrying the full design heat load of the room, with controls arranged so that the standby unit starts automatically on rising room temperature. Contractor shall furnish temperature sensors and an alarm interface that notifies the recipients identified by Owner. Contractor shall test standby operation by shutting down each unit in turn and shall record the room temperature response. Electrical service to the units is furnished by a licensed electrician designated by Owner.