Monday, April 20, 2009

A Long Way To Fall - Ladders Without Cages

This is a legacy ladder which was installed before OSHA even existed. However, that does not exempt the owner from correcting the situation. Ladders of this height must have an ANSI standard cage around them and a fall protection device installed.

Fall protection can be provide in two ways:

a.) There can be a continuous cable or track that runs the length of the ladder (usually up the centerline) with a special trolly attachment that ties to the front of the worker's fall protection harness.

b.) There can be a retractable fall arrest lanyard secured above the top of the ladder way that attaches to the back of the worker's fall protection harness.

Since the worker has to transfer backwards from the ladder onto the catwalk near the top, the retractable fall restraint would probably be the safer solution. Otherwise, the worker would be required to attach a secondary lanyard to the catwalk fall protection anchorage point before he could disconnect the front trolley and he would have to do that while standing on the ladder.

At the top of the ladder you can see that there is a fire sprinkler pipe crossing the travel path of the worker. This would have to be repositioned to provide proper clearance for the ladder cage. Right above the sprinkler pipe is the end of the Loading Gallery catwalk, which would also have to be moved back to allow a clear passageway. Fortunately, I had on my hard-hat when I climbed this ladder -- when I reached the sprinkler pipe I hit my head hard enough to dislodge the inner suspension. Had I not been wearing the hard-hat it could have knocked me out or made me lose my grip on the ladder.

A secondary problem with this stage design is that a full fly house really should have a Lower Loading Gallery in addition to the Upper Loading Gallery. The Lower Loading Gallery is typically situated about 10-12 feet (~4m) below the Upper Loading Gallery so that weights can be added / removed from the counterweight carriage (arbor) when the batten is about the height of a backdrop and/or scenery flat.

Of course, once the ladder has a cage around it and the end of the catwalk is repositioned, it will need a safety gate at the catwalk to keep someone from inadvertently stepping-off into the open hole. Something like this (from a different facility):

If you look closely you will see several interesting items in this picture:
  • On the left side (on stage), there is a railing that meets the 4" sphere rule (as if there was going to be a baby crawling around up there !? I guess they figured it was OK if the baby crawled under the safety gate . . .). There should be a steel plate or mesh that extends up about the 18-24" level to prevent the unused ( stored) counterweights from spilling over onto the stage floor below. Also note the 'stored' counterweight left along the off-stage side of the catwalk as a trip-hazard.
  • The on-stage side railing is also about 40" tall, enough to keep you from falling over it. A 42-48" railing would be more appropriate here.
  • On the right side (off stage, toward the counterweight arbors) there are railings at 8", 24", and 40". Just enough of them to keep you bonking your head as you try to man-handle the counterweights. There is not any OSHA required fall protection anchorage to allow the worker to wear a fall protection harness and safely lean-over the railing and do their work.
  • The floor of the Loading Gallery is fabricated from open pattern bar grate, which acts like a cheese grater on your knees when you kneel down on it. It is also open weave, so any grit on your shoes gets scrubbed-off and drops onto the crew working below you. A better solution is to have a closed floor decking (sheet metal) that has a dense rubber mat on it. This provides a non-slip surface, is quieter when setting-down counterweights, and keeps the grit from raining down on those below.
  • And the coup de grĂ¢ce is that there is not an Index Strip Light at this level, so you are working in the dark (all that light you see is from the camera flash). There wasn't any emergency lighting packs either, so if you get caught up there in the dark, good luck getting down!
As a side note, it is always good to paint the working surfaces facing the catwalks a light color like white. This is good for floors, railings, uprights -- everything. If the masking drapes are all properly positioned, no one will see the catwalk from the audience seating area. Place glow-in-the-dark marker tape along all gate and floor openings so you can find your way out in the event of a total power failure.

No comments:

Post a Comment