Good Evening all, I have recently had a discussion with my EHS manager over the correct maximum length that castor wheels can safely be threaded out the bottom of a mobile tower. He is saying that the wheels should not be threaded more than 100mm out of the bottom and that they are meant to be used to level the tower when working on non level ground. This came up during a site inspection where we witnessed two of our subcontracting trades were using towers and both had the wheels threaded out at there maximum of 300mm. the remainder of the castor leg which is not threaded is an additional 400mm. These were both single platform towers . If the operatives wound down the towers , they would not be able to reach the services that they were working on. My managers argument is that these should be no longer than 100mm , as it makes the tower unstable to work on. He also says that the contractor should have the correct equipment to work at that height, which I feel is right as our other contractors towers did not need to be wound out at all. My Argument is that if the castor leg is wound out to its maximum of 300mm, there is still a further 400mm of the castor leg within the tube. I appreciate these are to be used to level the tower on stairs etc. However if all four castor legs are wound out by 300mm and the castor wheels are locked when in use, I cannot see how this could make the tower less stable to work on. I can not find anything in the manufactures guide stating that the legs must be used at no more than 100mm and can not find anything to reference this in the work at height regs. Any help would be greatly appreciated. Regards, David

David, this is a M.I.M from one of the Manufacturers in the Pasma group. file:///C:/Users/Owner/Downloads/Nov11-BoSS-ladderspan-userguide_LoRes.pdf This is a section from it. It is recommended that for ease of levelling a gap of 50mm is left between the bottom of the leg and the adjustable nut. Adjustable Legs are for levelling only. You must not adjust all four to gain extra height. What concerns me is neither you nor your manager are aware of this when a direct requirement of the work @ height regs is that all work at height must be properly planned by competent people. Pasma have a course for Managers. The previous poster is 100% correct by saying use the M.I.M.

Certainly no intention to come across as harsh. If David and the EHS manager cannot agree on this, there appears to be a shortfall in competence of this subject. Nothing personal, just an observation. As for the other poster, he IS correct. He says MOST Manufacturers (Typically) use the system of having the collar as close to the base as possible. Some say a couple of threads, one says put your hand under the collar (about 100mm) but the vast majority say at or near the base. Did the OP not think to ask the tower assemblers? Surely they have received suitable and sufficient training in the safe use of towers...although you appear to have jumped on me from a great height without mentioning that. ;-) Just for clarification, OP who is are the Manufacturer's of the towers in question and are the assemblers using the 3T method or the AGR system?

If I was to take sides it would be Frank's. To support and add to what he says I would ask who checked the tower after assembly and was it fit for use? Is there a record of such a check and is that person competent? He/she will be able to answer the question, if trained and competent.

All, Thanks for the feedback. I have reviewed both manufactures guides for Boss - room mate tower. This includes the 3t method and the Stairspan tower user guide. Firstly I did not see any reference in the Boss manufactures guide to what height the castor wheels should be set at. In the Stairspan user guide under the erecting tower section it mentions " make sure tower is level and vertical" Then further down the page under whilst using tower section, it mentions " make sure castors are locked and tower is both level and vertical" Neither of them mention a specific height that the castors should be set at. So already it seems like quite a grey area. I finally found on the PASMA website on their FAQ page the following: If the tower is not high enough to complete the task is it acceptable to increase the height using the adjustable legs? Never use the adjustable legs on a mobile tower to gain extra height. The only purpose of the adjustable legs is to level the tower on uneven or sloping surfaces. At least one adjustable leg should always be on minimum extension. So going back to what frankc said regarding all work at height must be properly planned by competent people. If the information is not in the manufactures guide, how are you to know? Yes the person building the tower has to be PASMA trained. I have spoken to a few of our operatives onsite today who are PASMA trained as well as the PC's safety director who also happens to have PASMA. Neither of them could give me a definitive answer regarding this. Like I said earlier I do feel it is a grey area. As for the replies from the likes of frankc, what I would suggest is maybe take a step back and read your comments prior to sending them across. I have a good bit of experience under my belt however am still learning on a daily basis. Luckily I am thick skinned but I can imagine how a response like yours could discourage new users from posting questions on this forum.

Might need to copy and paste the Room-Mate M.I.M.