Poor roof drain design
As a plumbing contractor I really wish the manufacturers would ask us instead of an engineer how to design a roof drain that offers quality for a decent price without importing drains that are mix matched with component made in various countries .I install approximately 80 roof drains a year averaging over $1,500 per drain so I guess after doing these installations for over 30 years I know what a drain should have to be considered quality.
I would like a cast iron drain body with brass clamping ring / gravel stop and brass or stainless steel bolts long enough to allow the roofing contractors to use built up roofing like a 4 ply felt after I use my 4 PSF sheet lead. The galvanized bolts rust in making it impossible to loosen them when I new roof is required thus the drain also has to be replaced or sleeved
reducing drainage capacity which can allow dangerous ponding.
The castings on some of the drains coming into this country have a lot to be desired as the gravel stop does not match the bayonet dome locking slats and the casting are very brittle in some cases thus when making up the bolts the gravel stop cracks.
A leak from a faulty drain can cause hundreds of thousand of dollars in damages below.
It is plane ludicrous to use really cheap parts when the consequences can be quite disastrous in case of a leak below.