Childhood Adenotonsillectomy Trial

2.6 Calibration of Equipment

2.6.1 Stadiometer

Every day, calibration should be performed and recorded in a calibration log book. It is performed by measuring the height of the standard 600mm metal bar, in a white PVC pipe. If the standard 600mm metal bar does not measure 600mm, the supervisor in charge of equipment maintenance for the research equipment should be notified, who will contact Facilities Engineering or other appropriate parties to correct this.

2.6.2 Healthometer digital scale

The scale is calibrated once a week by using 20 k calibrated weights.

2.6.3 Tape measures

The length of the measuring tape is checked with the calibrated length rod (usually the 150 cm one) at least once per month. If the measuring tape is stretched or appears to have rippled edges it should be replaced. The type of tape measure recommended is an inelastic metric tape with a lead before the zero mark. Tape for waist and hip must be accurate to 0.1cm, and the tape for the neck should be 0.5cm wide.

Records of all calibrations should be maintained in a Calibration Log maintained by the CHAT Study Coordinator.