The upper limit temperature for pressure service is 140 degrees Fahrenheit . ln structural pipe, gravity flow application in stable oils; the upper thermal limit is considered to be in the range of 160F for long term exposure; and up to 180 degrees Fahrenheit for short-term intermittent exposure. The low temperature limit is usually regarded as minus 130 degrees Fahrenheit (seen next question). Cold temperatures do not adversely affect HDPE in static applications.