How to Test Raised Floor Airflow and Pressure in a Data Centre Malaysia
Many data centres use the space beneath a raised floor to distribute cooling air toward server racks.
If cables, floor openings, dirty filters or incorrect pressure conditions interfere with the airflow, some network racks may receive insufficient cooling even though the air-conditioning units continue operating.
Testing raised floor airflow and differential pressure helps Malaysian maintenance teams identify air-distribution problems before they cause rack-level hotspots or repeated high-temperature alarms.
How Does Raised Floor Cooling Work?
Cooling units deliver conditioned air into the space beneath the raised floor, which acts as an air-distribution plenum.
The air then enters the server room through:
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Perforated floor tiles
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Floor grilles
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Adjustable vents
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Openings designed for cooling delivery
The cooling air should reach equipment intakes before returning to the cooling system as warmer air.
Common Raised Floor Cooling Problems
Low Underfloor Pressure
Insufficient pressure may reduce the amount of air delivered through floor tiles.
Possible causes include:
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Air leakage
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Open floor panels
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Unsealed cable openings
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Insufficient cooling-unit airflow
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Dirty filters
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Fan problems
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Incorrect control settings
Uneven Airflow Between Tiles
Some floor tiles may deliver strong airflow while others provide very little.
Possible causes include:
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Distance from cooling unit
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Underfloor obstruction
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Cable congestion
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Incorrect tile placement
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Different tile designs
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Pressure variation
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Closed or damaged dampers
Cable Obstruction
Large cable bundles below the floor may block or redirect cooling air.
Unsealed Floor Openings
Openings around power and network cables may release cooling air at unintended locations.
Incorrect Perforated Tile Placement
Cooling tiles placed in hot aisles or unused areas may waste airflow.
Dirty Cooling Filters
Restricted filters may reduce total system airflow and increase the pressure difference across the filter.
Missing Floor Panels
An open raised-floor panel can release a large amount of air and change pressure throughout the system.
Tools for Raised Floor Cooling Inspection
A practical toolkit may include:
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Airflow meter
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Differential pressure meter
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Temperature and humidity meter
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Temperature data logger
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Thermal imaging camera
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Sound level meter
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Inspection light
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Floor-tile lifting tools used according to site procedures
Never lift raised-floor panels without approval and suitable safety controls.
What Does an Airflow Meter Check?
An airflow meter measures air velocity at:
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Perforated floor tiles
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Floor grilles
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Rack air intakes
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Cooling-unit outlets
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Selected underfloor openings
It helps determine whether adequate air reaches the intended location.
What Does a Differential Pressure Meter Check?
A differential pressure meter can compare:
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Underfloor plenum and server room
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Cold aisle and surrounding space
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Upstream and downstream of a filter
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Server room and corridor
For raised-floor testing, one pressure connection may be placed below the floor and the other at room level, according to the test method and instrument instructions.
Step 1: Review the Cooling Layout
Before measuring, identify:
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Cooling-unit locations
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Underfloor airflow direction
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Perforated tile locations
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High-load racks
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Reported hotspot areas
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Cable routes
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Known underfloor obstructions
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Previous airflow readings
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Floor openings and service penetrations
A layout drawing makes the measurement plan more effective.
Step 2: Check Cooling-Unit Status
Record:
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Which cooling units are operating
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Fan speed or operating mode
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Filter condition
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Supply-air status
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Active alarms
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Maintenance history
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Recent changes
Measurements from different operating conditions should not be compared directly.
Step 3: Measure Room Temperature and Humidity
Record the general server-room environment before testing raised-floor airflow.
Take additional measurements at:
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Cold aisle
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Hot aisle
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Front of problem rack
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Rear of problem rack
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Top, middle and bottom of rack
Step 4: Create a Floor-Tile Measurement Plan
Assign identification to each selected test point, such as:
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Tile A1
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Tile A2
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Tile B1
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Tile B2
Include:
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Rack number
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Aisle
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Distance from cooling unit
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Tile type
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Tile condition
This makes later comparison easier.
Step 5: Measure Airflow at Each Tile
For each floor tile:
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Confirm the airflow-meter unit.
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Hold the sensor at a consistent height.
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Keep the sensor orientation consistent.
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Avoid blocking the airflow with your body.
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Allow the reading to stabilise.
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Take several readings.
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Record the average where appropriate.
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Note the cooling-unit status.
For large grilles, take readings at several positions across the surface.
Step 6: Compare Airflow Between Tiles
Look for:
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One tile with very low airflow
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Large differences between adjacent tiles
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Strong airflow in unused areas
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Weak airflow near high-load racks
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Different readings from identical tiles
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Changes from previous inspections
The comparison may reveal an obstruction or pressure-distribution problem.
Step 7: Measure Underfloor Differential Pressure
Follow the instrument and site procedure.
Record:
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Positive-port location
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Negative-port location
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Measurement unit
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Door position
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Cooling-unit status
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Fan condition
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Exact floor location
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Time of measurement
Take measurements at several locations if the underfloor pressure may vary across the room.
Step 8: Check Pressure Across the Cooling Filter
Where permitted and suitable test points are available, measure the pressure difference across the filter.
A rising differential pressure may indicate increasing restriction, but results must be compared with manufacturer guidance.
Step 9: Inspect for Air Leakage
Check for:
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Unsealed cable openings
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Missing floor panels
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Damaged tiles
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Open unused penetrations
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Gaps around equipment
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Incorrectly positioned grilles
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Broken seals
Air escaping at unintended locations reduces the cooling available for critical racks.
Step 10: Inspect Underfloor Obstructions
Only authorised personnel should open raised-floor areas.
Possible obstructions include:
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Network cable bundles
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Power cables
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Unused cables
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Pipes
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Stored materials
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Construction debris
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Poorly arranged containment
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Damaged floor supports
Do not disturb critical power or network cables during inspection.
Step 11: Check Rack Inlet Conditions
Low floor-tile airflow does not automatically confirm that equipment cooling is inadequate.
Measure temperature and airflow at the rack inlet, especially at:
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Bottom
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Middle
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Top
Compare problem racks with nearby normal racks.
Step 12: Perform Thermal Scanning
Use a thermal camera to inspect:
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Rack fronts
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Rack rears
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Top of racks
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Cooling-air paths
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Hot and cold aisles
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Server equipment
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PDU connections
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Cooling-unit motors and electrical components
The Noyafa NF-522 Thermal Camera can help locate the temperature effect of poor airflow.
Step 13: Install Data Loggers
Place data loggers at:
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Problem rack inlet
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Reference rack
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General room area
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Cooling-unit supply area
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UPS area where relevant
The Elitech RC-5 can record temperature over time.
A suitable temperature-and-humidity logger such as the Elitech GSP-6 Pro may be used when both parameters are needed.
Step 14: Correct the Confirmed Problem
Possible corrective work includes:
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Seal cable openings
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Replace missing floor panels
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Remove approved obstructions
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Improve underfloor cable management
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Clean or replace filters
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Repair cooling fans
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Adjust tile position
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Balance cooling airflow
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Correct containment gaps
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Install rack blanking panels
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Adjust cooling controls
Changes should follow the approved data-centre procedure.
Step 15: Repeat the Measurements
After correction, repeat:
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Floor-tile airflow readings
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Underfloor pressure measurements
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Rack inlet-temperature readings
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Thermal scanning
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Data logging
Use similar cooling-unit and room conditions for a meaningful comparison.
Example: Weak Airflow at One Floor Tile
Possible causes include:
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Obstruction directly beneath the tile
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Closed tile damper
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Different tile type
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Cable congestion
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Damaged grille
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Local pressure difference
Compare neighbouring tiles and inspect below the floor only when authorised.
Example: Weak Airflow Across Several Tiles
Possible causes include:
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Low underfloor pressure
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Dirty cooling-unit filter
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Fan problem
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Large air leak
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Missing floor panel
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Cooling unit not operating
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Incorrect system setting
Measure pressure and check the cooling unit.
Example: Strong Tile Airflow but Rack Is Still Hot
Possible causes include:
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Air missing the rack intake
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Hot-air recirculation
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Blocked server inlet
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Missing blanking panels
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High rack load
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Failed equipment fan
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Incorrect rack orientation
Use a thermal camera and rack-level temperature measurements.
Example: High Underfloor Pressure but Low Rack Airflow
Investigate:
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Tile restriction
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Closed dampers
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Incorrect grille
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Blocked rack intake
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Poor tile position
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Airflow bypassing the equipment
Pressure alone does not confirm effective cooling at the rack.
Airflow Meter Versus Differential Pressure Meter
| Raised-floor test | Airflow meter | Differential pressure meter |
|---|---|---|
| Measure velocity from floor tile | Yes | No |
| Compare tile output | Yes | No |
| Measure underfloor pressure | No | Yes |
| Check pressure across filter | No | Yes |
| Confirm air reaches rack inlet | Yes | Supporting evidence |
| Identify pressure imbalance | No | Yes |
Use both when investigating complex air-distribution problems.
Common Raised Floor Testing Mistakes
Avoid:
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Measuring only one floor tile
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Comparing different tile types without noting them
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Holding the airflow sensor at different heights
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Blocking airflow with the technician’s body
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Failing to record cooling-unit status
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Measuring pressure without identifying both test points
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Opening floor panels without authorisation
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Moving critical cables
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Assuming high underfloor pressure guarantees good rack cooling
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Ignoring unsealed cable openings
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Failing to retest after correction
What Should Be Included in the Report?
Include:
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Server-room layout
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Cooling units operating
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Measurement date and time
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Room temperature and humidity
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Floor-tile identification
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Airflow readings
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Differential-pressure readings
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Test-point locations
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Filter condition
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Underfloor observations
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Rack inlet temperatures
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Thermal images
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Data-logger records
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Corrective actions
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Follow-up results
Recommended Raised Floor Inspection Kit
A practical kit may include:
-
Airflow meter
-
Differential pressure meter
-
Temperature and humidity meter
-
Elitech RC-5 Data Logger
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Elitech GSP-6 Pro
-
Noyafa NF-522 Thermal Camera
-
Sound level meter
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Inspection accessories approved for the facility
Confirm That Cooling Air Reaches the Equipment
Raised-floor pressure and tile airflow should not be assessed separately from rack temperature.
A complete investigation checks how air moves from the cooling unit, through the underfloor plenum and floor tile, into the network rack and back toward the cooling system.
Combining airflow, pressure, temperature and thermal measurements helps data-centre teams identify where the cooling path becomes restricted or inefficient.
Contact MTM Precision
MTM Precision Sdn. Bhd.
Showroom & Service Centre
No. 29-1 & 29-2, Jalan Bandar 18,
Pusat Bandar Puchong,
47160 Puchong, Selangor, Malaysia
🌐 Website: www.mtmpre.com.my
📧 Email: mtmpre@yahoo.com
📱 WhatsApp: +6016-660 7346
02 Sep 2026
