Truss protectors and 1 1/4" pipe

[BillConnerFASTC]

Despite many mentions and sketches during design, and reviews of both contract drawings and shop drawings, once again the miscellaneous metals contractor installed 1 1/4" pipe instead of the detailed 1 1/2" pipe for a couple of FOH lighting positions. Schedule among many issues makes it difficult to force them to change it.
I'd like to know if the typical truss protector - like http://www.pnta.com/scenic/rigging/...4qZ5Da_K2ODONr__EtlXAlcZfouBflAxrwaAq-R8P8HAQ - will stay on an 1 1/4" pipe and somewhat alleviate the frustration of larger clamp adjustments. Worth it? (Contractor would have to buy these so not spending any owner money.)

 

[TJCornish]

I have not used that product, but I have made a number of them out of 1 1/2" PVC pipe with a chunk cut out. That allows the 2" nominal clamps to tighten appropriately. Cutting out about 1/2" of the PVC seems to be a good balance between staying on and intentional removability.

If the product in your link is already designed for a 2" pipe I suspect it would not stay attached to your 1 1/4" pipe.

 

[Van]

Aww, C'mon! Put your foot down, tell 'em to read the spec and tear it all out! .... Yeah I know. what a PITA! I'll have to share some HVAC installations I've dealt with lately...

 

[BillConnerFASTC]

2" as in 1 1/2" nominal pipe size - approx 1 7/8" OD - versus the installed 1 1/4" - approx 1 5/8" OD - just a 1/4".

Yes - could make out of pvc pipe but if a GC is being let out of a many thousands of dollars liability, let him spend the $100 for some nice pipe condoms.

 

[BillConnerFASTC]

I agree that if there is an obstruction that won't allow it the normal and intended use, and it was reasonably clear in the contract documents, they have to eat it. On the other hand, its hard to say that if the rail on on the face of a balcony is 1/4" smaller diameter than intended, that it is unusable or even greatly changes the function. I believe in being fair to all parties involved in the construction of a facility, and have not done this for 35 years without having need the fairness and understanding of the other parties myself. And at this stage of the project - most concrete work done and many steel studs in but that's about it - the school or I may yet need some consideration - especially considering it's a 100 year old existing building that has suffered one awful renovation in its mid life years. Now, if a rigging contractor is low bid and a year into the project says we can't and won't do what we bid on, that's a little different than asking to substitute a different piece of hardware. I just don't think any of the various parties to the design and construction of an auditorium and stage should assume slave or slave owner status, and fairness should triumph.

 

[derekleffew]

2" as in 1 1/2" nominal pipe size - approx 1 7/8" OD - versus the installed 1 1/4" - approx 1 5/8" OD - just a 1/4".

Yes - could make out of pvc pipe but if a GC is being let out of a many thousands of dollars liability, let him spend the $100 for some nice pipe condoms.

I don't think I've ever seen a standard c-clamp that wouldn't work on 1 1/4 as well as 1 1/2. If we're thinking about moving light clamps: Mega-claw, half-coupler, trigger clamp, and the like--those won't work with truss protector s. I should say, won't work well with truss condoms, especially the City Theatrical that has a lip on one side. Conundrum.

 

[MNicolai]

I don't think I've ever seen a standard c-clamp that wouldn't work on 1 1/4 as well as 1 1/2. If we're thinking about moving light clamps: Mega-claw, half-coupler, trigger clamp, and the like--those won't work with truss protector s. I should say, won't work well with truss condoms, especially the City Theatrical that has a lip on one side. Conundrum.

I think I encountered this 7-8 years ago. Think the ETC clamps don't (or didn't?) come with long enough bolts for this and I had to swap all of the clamps' pipe bolts out with longer ones so they close down the 1-1/4" pipe (vaguely recall that being an Altman part #?). Also means when you move back to 1-1/2" pipe you have to back that bolt out several turns.

When I've done it, I was using truss and PVC protectors. Worked...well enough...if the fixture was hanging in a normal orientation. If the fixture was a front-heavy zoom or had to be roostered in any direction though, there was no feasible way to get enough grip between the clamp and the pipe and fixtures would spin on the truss just enough to reliably drop focus. In my case that probably had more to do with using the PVC protector, but it also has to do with the clamps having less surface area to grip onto the pipe.

 

[jaightaylor]

Not that I'd ever deface US currency... but pennies work quite well.

 

[TJCornish]

If we're thinking about moving light clamps: Mega-claw, half-coupler, trigger clamp, and the like--those won't work with truss protector s. I should say, won't work well with truss condoms, especially the City Theatrical that has a lip on one side. Conundrum.

They do, however, work fine with homemade PVC pipe sleeves that don't have a lip, and are necessary because the Mega-claws and others don't close down enough to grip 1 1/4" pipe.

 

[GreyWyvern]

Not that I'd ever deface US currency... but pennies work quite well.

The problem with pennies is them not staying in place. Hence, the Perma Penny!
@BillConnerFASTC, any reason these wouldn't work?

 

[RickR]

Since these are intended to be permanent and the plastic is intentionally 'sacrificial' could the offending pipes have a 2 part aluminum or steel cover glued or welded onto the critical areas?

I've never worked with the Perma Penny but I can't imagine any of these lasting 20+ years.

 

[egilson1]

I'd go in the direction of getting a clamp that closes down on the pipe. Many of the aluminum clamps will work well, and then the end user is never needing to deal with a spacer that is ultimately probably probably crack or get lost.

 

[Jay Ashworth]

I'm curious:

Would lighting-batten pipe diameter not be a "critical" dimension, and so marked on a construction print?

Could one expect an installation GC to respect dimensions so marked? Or not?

 

[JohnD]

It also brings up the concept of if a contractor is subbing a cheaper material in one place, how about in other areas?

 

[BillConnerFASTC]

I'm curious:

Would lighting-batten pipe diameter not be a "critical" dimension, and so marked on a construction print?

Could one expect an installation GC to respect dimensions so marked? Or not?

Yes - the Owner could force - not pay till it's done right - the contractor to cut out all the lighting rails and replace with 1 1/2" pipe. Could even charge them liquidated damages because it made the project finish late - but of course they don't have the space for when it was already scheduled to be in use. You also have a pissed off contractor, who will try to make it up somewhere else, and probably will. I just don't think treating the contractors as adversaries is a very good long term - or short term actually - strategy. I see it a lot, and you might win one or two but they usually turn out to be Pyrrhic victories. Works out better when all sides admit their mistakes and all work together to come to a satisfactory solution in my experiences.

 

[Jay Ashworth]

And I'm not debating that, but my *point* was more "can't we *avoid this* in the first place?"

 

[BillConnerFASTC]

It also brings up the concept of if a contractor is subbing a cheaper material in one place, how about in other areas?

One would think that anyone involved in design and construction of buildings would know that 1 1/2" pipe referred to the ID but some people don't, and this seems to lead to others second guessing - did that person mean 1 1/2" pipe or did them mean they wanted a round steel tube which was 1 1/2" outside diameter. I doubt if cost is the reason - more ignorance or second guessing complicated that most handrails and guard rails are 1 1/4" pipe (and 1" would be better for handrails for graspability.)

Its not quite every other project, and I've learned to make a big f...ing. deal of the issue at the beginning, middle and end of design, and the beginning, middle and end of construction, but it doesn't always trickle down to the right people, and there are a lot of people in the chain.

 

[JohnD]

Perhaps it would be cheaper for them to supply a suitable number of these:
http://www.thelightsource.com/products/mega-swivel-16
or these:
http://www.thelightsource.com/products/versi-clamp-42

 

[BillConnerFASTC]

I think egilson1's idea of making sure the clamps will work is probably the simplest, but some battens are 1 1/2", so they do have to work both ways. I thought about welding a 1/4" by maybe 1/2" "bar" on top of the pipe but at least the balcony rail would look not nice, and the chance of wanting to use a side arm here or to rooster is slight but not impossible - so more problems.

And I'm not debating that, but my *point* was more "can't we *avoid this* in the first place?"

I think my response to JohnD addresses this but I - and I know others - would say no. There is a way - pay enough to have the theatre consultant on site weekly or more often. That would avoid these problems and others, and double or triple my fee for the project. Unfortunately, site visits are the first thing to get attacked and cut when they need to reduce fees. I just started by sub-contracting to a person I know that lives very close to a project. They know theatre, are cheap relatively (as well as retired in one case), and hopefully will be good frequent eyes on the project. We'll see. It is money out of my pocket, but hopefully it will save me time (I'm 7 hours away - each way) and make for a better project.

 

[BillConnerFASTC]

Perhaps it would be cheaper for them to supply a suitable number of these:
http://www.thelightsource.com/products/mega-swivel-16
or these:
http://www.thelightsource.com/products/versi-clamp-42

Actually - I do - this one or the one by Apollo or the one by Doughty sometimes. I want the load rating. But that doesn't overcome the irritation of having to run the bolt a lot more when changing from one position to another, or the slight propensity to not bother tightening it for a few minutes hang on a rail before final hang, or having to open it to just get started. It's a pin in the butt, or we would not worry about it.