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Safety and Buildings Division Explanatory material for testing of below-ground cylinders The March 2004 Wisconsin
Administrative Code Comm 18 and the adopted American Society of
Mechanical Engineers (ASME) A17.1, 2000 National Safety Code for
Elevators and Escalators contain several changes to previous codes
governing elevator hydraulic jacks. Among the changes effective April
1, 2004 are requirements for testing the hydraulic cylinders of
elevators contracted to be installed prior to January 1, 1975 and that
have any part of the hydraulic cylinder below ground. An in-ground elevator hydraulic jack consists primarily of a cylinder (similar to a pipe) capped on the bottom, a plunger (similar to a piston), and a ring-shaped head. The cylinder is inserted into a vertical hole drilled or bored in the soil beneath the elevator. The plunger is inserted into the cylinder and the head is installed around the plunger at the top of the cylinder. The top of the plunger is attached to the underside of the elevator car. When oil is forced into the cylinder under pressure by the elevator hydraulic pump the plunger is displaced causing the plunger and the elevator car to rise. This operation is similar to a hoist used to raise an automobile at a repair center or a hydraulic ram on a piece of construction equipment. Single-bottom hydraulic jack A single-bottom hydraulic cylinder will have one plate or disc welded to the bottom of the vertical pipe. In the course of investigating single-bottom jack failures, it has been discovered that corrosion and failures tend to occur at this weld joint. Failure of the bottom can cause a rapid loss of oil causing the elevator to drop. Injuries and deaths have been reported as a result of such failures. To address this, the double-bottom (also called "safety-bulkhead" type) cylinder was developed. Double-bottom hydraulic jack A double-bottom or safety-bulkhead cylinder has one bottom or disc welded just inside the bottom of the vertical pipe. In addition, a cap or second bottom is welded below the first bottom. Since the welded joint attaching the second bottom may be exposed, it may be prone to corrosion and failure. The first bottom is provided with a small orifice or hole so such a failure of the second bottom will be indicated by the elevator descending in a controlled manner as oil escapes the cylinder through the orifice in the first bottom (the safety bulkhead). Elevator in-ground hydraulic cylinders have been required to be of the double-bottom type in Wisconsin since January 1, 1975. Testing of single-bottom jacks In an effort to assess the condition of existing single-bottom cylinders, the March 2004 Wisconsin Administrative Code Comm 18 requires jacks installed prior to January 1, 1975 to be tested. Tests are to be conducted by qualified elevator personnel in accordance with ASME A17.1, 2000 edition, Requirements 8.11.3.2.1 and 8.11.3.2.2. Req. 8.11.3.2.1 requires qualified elevator personnel to pressurize the elevator system to the system relief pressure. This is the pressure at which the relief valve operates and is not to exceed 150% of the normal system working pressure. For elevators where the hydraulic control valve relief pressure adjustment is not sealed or is not properly set, qualified elevator personnel must load the elevator with weights equal to the full capacity of the elevator. The elevator must lift this load at normal, rated speed to determine the system working pressure. The relief pressure must be adjusted if necessary, and sealed if the adjustment has provisions for sealing. The working pressure, relief pressure and other information must be recorded on form SBD-3-E. Req. 8.11.3.2.2 requires qualified elevator personnel to park the elevator for a period of 15 minutes (no load is required). The starting and ending positions of the car and oil levels and other information are recorded on form SBD-3-E. If the elevator changes position (downward) and the change cannot be explained by visible oil leakage, leakage through the control valve or temperature change, a leak is occurring in the portion of the cylinder below ground. Failure of either test may warrant immediate shut-down of the elevator by qualified elevator personnel or an inspector. If not done by qualified elevator personnel or an inspector, the owner must take the elevator out of service. Replacement of the in-ground hydraulic cylinder will be required at that time. Prior to replacement of a cylinder approval must be applied for by the owner or contractor and issued by this department. See form SBD-22. Deadline for completing the testing From April 1, 2004 through March 31, 2005, the elevator annual inspection may be completed and the permit to operate (PTO) issued without completing these tests. If the tests are not complete the inspector will note on the inspection report that the following year's PTO will be withheld unless the tests are shown to have been satisfactorily completed before the next annual inspection. Failure to show satisfactory completion of the tests prior to the expiration of the PTO between April 1, 2005 and March 31, 2006 will result in withholding of the permit to operate at that time. Alternatives to testing For elevators with in-ground cylinders installed prior to January 1, 1975 testing is not required if one of the following is provided to this department: 1). Conclusive evidence showing the original jack is equipped with a double bottom. In some cases it may be possible for qualified elevator personnel to identify a jack based on nameplate data, jack head type or original installation records. 2). Conclusive evidence showing the original jack has been replaced with a jack equipped with a double bottom. 3). A satisfactory application to install a car safety device meeting A17.1a [2002 Addendum], Section 3.17. Approval must be applied for by the owner or contractor and issued by this department prior to installation of the car safety device. Please note that a plunger gripper is an approved hydraulic elevator safety device per this addendum however bottom runby must be provided. If installation of a plunger gripper will result in reduction of runby below allowed limits, a petition for variance must be submitted showing runby, clearances and operation providing an equivalent degree of safety. 4). A satisfactory application to replace the existing jack. Record of oil usage As of April 1, 2004, the owner of a new or existing elevator is required to keep a maintenance log for the elevator (see Req. 8.6.1.4). In addition, the owner of a new or existing elevator with an in-ground hydraulic cylinder or piping is required to keep a record of oil usage per Req. 8.6.5.7. If unexplained oil loss occurs, the above tests must be performed immediately. As stated above, failure of these tests may warrant immediate shut-down of the elevator by qualified elevator personnel or an inspector. If not done by qualified elevator personnel or an inspector, the owner must take the elevator out of service. Failure will require replacement of the in-ground hydraulic cylinder. Approval must be applied for by the owner or contractor and issued by this department prior to replacement of a cylinder. Links -- County Web sites || City/Town/Village Web sites || State Portal || Licensing and Permitting || Build Your Business Email this page's manager, Todd Taylor, ttaylor@commerce.state.wi.us or 608-267-3606 The Department of Commerce Safety and Buildings Division is an equal opportunity service provider and employer. If you need assistance to access services or need material in an alternate format, please contact us, 608-266-3151, TTY 608-264-8777, or ttaylor@commerce.state.wi.us |
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