Anyone ever frustrated while looking for the site of a pressure-relief valve release may appreciate a device that debuted at the annual meeting of the International Institute of Ammonia Refrigeration in Orlando this week.

Tattle, a relief-vent indicator, can be installed on the outlet of a pressure-relief valve to alert operators to the site of releases of gases such as ammonia or Freon. The device provides visual indication via a flag that is activated when a release allows gas passed the vent-relief indicating device. According to the manufacturer, the device tells the operator that the pressure-relief valve has relieved even after the conditions that caused it to relieve have been corrected. The vent-relief indicator can be reset once triggered.