Hydrostatic Testing Services

hydro teting

Hydrostatic Testing Procedure

Industrial Protection Services is able to provide hydro testing for both S.C.B.A. and DOT storage cylinders. We provide mobile on-site hydro testing services for all S.C.B.A. cylinders however; all DOT cylinder testing is performed in our Wilmington MASS service center.  Industrial Protection Services technicians are trained and certified to meet DOT requirements and our facility is licensed, certified, and monitored by the U.S. Department of Transportation.

Testing Schedule

Periodic hydrostatic testing is a DOT 49 CFR 180.205 requirement to be met by all entities that use DOT and Special Permit cylinders i.e. S.C.B.A. and DOT storage cylinders (used on compressors or cascade systems). The frequency of the maintenance depends upon the material used to manufacture the cylinder.

  • Steel and aluminum cylinders should be tested every five years. They have an indefinite service life as long as they pass hydrostatic testing. 
  • Aluminum cylinders (not including hoop-wrapped) should be tested every five years. They have an indefinite service life until they fail a hydro test. 
  • Hoop-wrapped cylinders should be tested every three years. Hoop-wrapped cylinders have a 15-year service life. 
  • Fully wrapped fiberglass cylinders should be tested every three years. They have a 15 year service life. 
  • Fully wrapped Kevlar cylinders should be tested every three years. They have a 15-year service life. 
  • Fully wrapped carbon fiber cylinders should be tested every five years. They have a 15-year service life.

Cylinder Safety

Cylinders should not be filled if they have exceeded their valid service life or re-test dates. Cylinders which show evidence of exposure to high heat or flames (paint turned to a brown or black color, decals missing or gauge lens melted) need to be removed from service and be visually inspected and hydro-statically tested prior to recharging.

Visual Inspections

Visual inspections should also be performed on a regular basis as recommended by the DOT. The visual inspection should include, but is not limited to, removing the cylinder valve, inserting a high-intensity light probe and angled mirror into the cylinder and examining the inner surfaces of the cylinder. This inspection is necessary to aide in identifying defects in the inner surfaces of the neck and shoulder area of the cylinder

Hydrostatic Testing

S.C.B.A cylinders are normally tested using a water jacket test. The vessel is visually examined for defects and then placed in a container filled with water, and in which the change in volume of the vessel can be measured by monitoring the water level. For best accuracy, a digital scale is used to measure the smallest amounts of change. The vessel is then pressurized for a specified period, usually 30 or more seconds, and then depressurized again. The water level in the jacket is then examined. The level will be greater if the vessel being tested has been distorted by the pressure change and did not return to its original volume, or some of the pressurized water inside has leaked out. In both cases, this will normally signify that the vessel has failed the test. If the percentage of permanent expansion is more than 10%, REE (rejection elastic expansion) is exceeded or cylinder does not meet CGA criteria, the cylinder fails, and then goes through a condemning process marking the cylinder as unsafe.

Cylinder Identification

All the information the tester needs is stamped onto the cylinder or provided on a label from the manufacturer. This includes the DOT information, serial number, manufacturer, and manufacture date. Other information is stamped or labeled as needed such as the REE (or how much the manufacturer specifies the cylinder should expand before it is considered unsafe). All this information is taken down and stored on a computer prior to the testing process. This information is necessary for keeping track of when the cylinder has been or needs to be hydro tested.