DESIGN FEATURES OF AN UNDERGROUND METROLOGY LABORATORY

The basic requirements for an ideal Metrological Laboratory are:

The Room:

1. Should be below the ground level to certain meters (say 6m), to take advantage of constancy of underground temperature and to isolate it from the vibrations, acoustics and other external influences, which affect the lab environment.
2. Should be insulated with expanded polystyrene insulation on all six sides.
3. Should have double walls with air gap on all the four sides to be made.
4. Should have special RCC floor blocks, cooled with circulation of chilled water is required.
5. Should have swirl type air diffusers to be fixed for thorough air mixing.
6. Should have an system so return air flows all along the wall surface.
7. Should have a high 30 air changes per hour.
8. Should have an air shower and air lock at entry, to keep the environment controlled under standard requirements.
9. Should have a vibration damping foundation with massive 1.5m monolithic RCC blocks. 
10. Should have Anti-static PVC flooring.

Environment

1. For effective handling of instruments and stainless checking of the readings, high efficient fluorescent lamps to be used as per NABL recommendation.
2. Importance to be given in temperature and humidity control all over the lab premises by strategically locating sensors and direct digital control.
3. Stainless steel pipes and fittings should be provided for compressed air supply system.
4. Separate pre-cleaning room with ultrasonic cleaning machine to be maintained.
5. Separate material stock room for storage of the calibrated instruments and gauges is a must.
6. Built-in emergency lighting and fire alarm system to be installed as a preventive maintenance inside the calibration laboratory.

Parameters to be considered before designing for the underground metrological laboratory.

PARAMETER	METROLOGY LABORATORY
Temperature	20 ± 0.2° C
Humidity	50 ± 5% RH
Clean room Class	10,000 (5VDI 2083)
Air velocity	< 0.2 m/sec
Differential Air Pressure	> 10 pa (1mm Wg)
Ground vibration (@<10 Hz)	< 0.2 µm
Illumination	400 lux
Noise level	< 45 dB (A)
Floor covering	Anti static PVC
Area	200 – 250 Sq.m.