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Posted on Wednesday, December 14, 2005 - 04:39 pm:   Edit PostDelete PostPrint Post

We choose to post anonymous due the fact that we are a roof drain manufacture and do not wish to be viewed as promoting our product in this discussion board. What we want to know is there anyone else out there who feels that we may be headed for trouble with roof drains.
For decades the roof drain industry has produced high quality products in regard to design and flow characteristics, but as of recent years even though the quality products are still made they are not always making it into the projects. We tracked a job in recent months and found that even though a proper performing large body roof drain was specified, a small combination drain was installed. This due to value engineering by someone. A spec sheet on this product even states for use on small roofs, but it was installed in the main roof area of a large building.
Some of the manufactures have done some flow testing of roof drains throughout the years and the result appears to be larger drain bodies flow higher capacities and small bodies flow lower capacities, not all roof drains are created equal. That is why drain manufactures have so many different configurations. The sump/body size for a 4 drain can range from 5 thru 12. A flow test we have seen for the small combination drain with a 5 sump/body is exceeding the overflow elevation at 58 GPM and the rated flow for a 4 pipe sloped 1/8 per foot is 79 GPM. It also showed that at 120 GPM both the primary and overflow inlets were flowing and required 4 of head. The vertical leader value for a 4 drain is 192 GPM. So you probably have a system that the overflow is flowing most of the time which then becomes just another primary system with no overflow.
What concerns us is, roof drains are not the best maintained fixtures in a building and if the fixture is struggling to flow in perfect test conditions what is going to happen in the real world with debris. It is also that there really is no warning that the roof drain is not keeping up and the result can be catastrophic and people could get killed.
So who would be liable the Manufacture, Rep, Engineer, Architect, Contractor or the Building Owner? This is not just a once in a while situation we have been talking to wholesalers throughout the US and they say they sell a lot of them. We also are not attacking any one manufacture most all have a comparable product. We just think we are in a dangerous area.
J. Peter Jordan
Senior Member
Username: jpjordan

Post Number: 162
Registered: 05-2004
Posted on Thursday, December 15, 2005 - 09:24 am:   Edit PostDelete PostPrint Post

If the value engineering process required review and approval by the A/E, then the A/E has "designed" (product selection is one aspect of design) and is liable.

If the VE process takes place without A/E review or if the proposed VE item is approved by the Owner over the objection of the A/E, then the installed product does not meet the requirements of the Drawings and Specifications. The Contractor has to assume some design liability; however, the Owner's acceptance of this item may mean the Owner is stuck.
William C. Pegues, FCSI, CCS
Senior Member
Username: wpegues

Post Number: 509
Registered: 10-2002
Posted on Thursday, December 15, 2005 - 12:02 pm:   Edit PostDelete PostPrint Post


J. lists a perfect example as relates to VE type items. We see this kind of situation all the time with numerous products. The VE system that tends to happen most of the time is that the contractor gives a list of items to the Owner, the owner asks our opinion. There are things we will do, and not do and advise him of such.

By 'we', I also maen our consultants, not just the architect. And we base our response on the interaction of the suggested VE, not just each item alone without the context of its use or other related proposed changes.

But this 'we' does not include what has become a big trend in high rise residential projects - the use of 'design build' MEP on projects. Those are direct between the Owner and the Contractor. We offer advise based on what we can learn about it, coordination information, etc., but even that is hard to come by. We provide our information to them, and it is often ignored.

As an example of some really bad encounters with this kind of work would be a project where we sized a room for equipment, provided it very early with requests for sizing requirements if it was too small, no imput. Then during construction they come back and want a room that is about 3 times larger because they intended to layout the equipment widely spaced and only at 'eye level' for convenience of installation. Or another where only at the time they are going to install it the item is much larger than what everyone was assuming based on typical practice (and no earlier input from them).

Those kinds of projects are just laden with problems, and it is in their scope to include the roof drains. I have seen what you are talking about, drains that are intended for small areas being put on buildings totally inappropriate for their use. But when they split out this to a 'design build' MEP, it takes it out of our control. Sometimes we don't even know (nor even the owner) what is being installed until after it is installed.

Now a lot of that problem is really the Owner's responsibility for having a contract that has so little in the way of coordination performance on the part of the 'design build' group. And its also a problem where an Owner does not have the internal expertise in his own organization to actually monitor the design build group appropriately.

I do have to say that though Contractors propose these scopes of work as 'design build' to Owners, it is not really a design build process by any accepted definition of the term. Design build can be a very useful process - but not as how these kinds of contracts are being set up.


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