Single Bottom Cylinder Replacement

Mar 19
2013

Category: Modernization

Single Bottom Cylinder Replacement

Provincial regulations recently changed with the BCSA issuing  Safety Order SO-L1 101214 1  which requires the modification of all existing single bottom cylinder elevators by October 8, 2015.

The Safety Order applies to all hydraulic elevators installed below ground with single bottom cylinders. Most single bottom cylinders have been in the ground for 30 years or more. The potential for catastrophic failure due to the separation of a single bottom from the cylinder increases with cylinder age.



WHY?

Prior to 1977, the industry standard for cylinders was a single bottom cylinder design. The compounding problem is that most of these cylinders were also installed without a PVC casing which leaves the cylinder unprotected from corrosion. The electrolytic action causes the steel cylinder to corrode and burst. When this happens the column of oil supporting the elevator is expelled into the surrounding earth and the elevator drops in free-fall.

 

RISKS

•The original design cannot control the speed of descent if the bottom plate ruptured which would allow all of the oil to escape at once and resulting in a catastrophic failure

•Rapid oil loss causes car to descend out of control

•This may result in injury or death, property damage and environmental contamination

 

DOUBLE BOTTOM CYLINDER DESIGN

After 1977 the double-bottom cylinder design became the industry standard to protect against failure of the bottom plate.

•This new cylinder design features a bottom plate plus a safety bulkhead equipped with a relief orifice.

•The orifice is designed to limit the speed of the elevator’s descent should a bottom plate rupture occur

 

 

OPTION 1 –Replace Cylinder with Double Bottom

Advantages

•Eliminates the risk of failure

•Eliminates the risk of soil contamination

Disadvantages

•Approximate shut down times of 4–6 weeks

•Unknown soil conditions may add additional costs

 


OPTION 2 –Install a Piston Gripper

Advantages

•Eliminates the risk of failure

•Shorter shut down period

Disadvantages

•Does not eliminate the risk of soil contamination

•Should the cylinder fail at any time in the future it will still require replacement resulting in further cost.

 

 

OPTION 3 –Install Car Safeties and Governor

Advantages

•Eliminates the risk of failure

•Shorter shut down period

Disadvantages

•Does not eliminate the risk of soil contamination

•Should the cylinder fail at any time it will still require replacement

•An engineer must investigate and approve the design. This may require structural modifications to the hoistway and unknown additional costs.

•Rails may not be capable of supporting system

 

 

OPTION 4 –Replace the Elevator

Advantages

•Complete new system ensures that all components are new

•In ground cylinder is replaced with either a machine room less traction elevator or an above ground dual piston

Disadvantages

•Longer shut down period of 6 – 8 weeks

•An engineer must investigate and approve the design. This may require structural modifications to the hoistway and unknown additional costs.

 

 

Here is an interesting story on CTV regarding Single Bottom Cylinder Replacement

http://bc.ctvnews.ca/residents-angry-over-40-000-mandatory-elevator-fix-1.938302

 

 

 

Eltec Elevator Ltd. is specialized in the maintenance, repair and modernization of elevators in residential, commercial and institutional buildings within the Lower Mainland.

 Since 1982, we have been fully committed to developing long lasting partnerships with our customers by providing innovative elevator services with a personal touch.

 We maintain, repair and modernize elevators in following areas: Burnaby, Coquitlam, Delta, Langley, Maple Ridge, Abbotsford, New Westminster, North Vancouver, Pitt Meadows, Port Coquitlam, Port Moody, Richmond, Surrey, Tsawwassen, Vancouver, West Vancouver, White Rock, Mission and Chilliwack.