2.2.13 Airtightness (1) Testing Drill a hole in the housing of a water-proof connector or pass a pipe through one of the cavities in the connector. As immersed in water, the connector shall have both positive and negative pressures applied through the hole or pipe to determine the airtightness. In this case, keep returning all the leads into the connector. (See Fig.2.2.13.) To determine the airtightness, put the connector into water to a depth of about 10cm below the water surface and send compressed air of 9.8kPa for 30s. Unless the air has leaked for a period of 30s., raise the pressure every 9.8kPa.(2) Performance Either initially or after completion of the endurance test, the connector shall neither water enter nor air leak at both positive and negative test pressures (98kPa).