At best, I think Flashing should be referenced in your Division 8 specs, and then be in its own section under Division 7. Different trades provide these different materials, so separating them makes sense to me. I realize that may be a heretical statement under the concept of “work results”, but I am a full time Construction Administrator, and this is how the real world works out in the field.
Depends what Flashing we are talking about. If it’s transition flashing as part of the air barrier, then I would put it in 07 with the air barrier as an accessory. If it is misc. brake metal flashing that is intended to complete the CW/SF system, then I’d keep it with the SF/CW.
If it’s metal sill flashing i’d keep it in CW/SF. Stainless steel concealed flashing could go either way.
I’ve seen details where the stainless steel brake metal flashing in the Division 08 fenestration specs interfere with the aluminum sill flashing but that is a detailing issue, not a spec issue.
Some firms opt to use stainless steel flashing to close off the back and top (cap) of mullions. I prefer to use extruded aluminum for those conditions. As long as you close them off, I guess the choice is yours. Some manufacturers show jamb mullions as being open backed; I don’t know why. Very often doors, frames, and mullions do not get capped properly and permit free-flow of water. Apparently if you don’t require it in your spec, you will not to get it. Again, this should be clearly shown in your details as well. How they presume to meet performance requirements as part of their delegated design without it is beyond me but we have seen projects when doing forensics on other firms’ projects where it wasn’t shown specified, or provided.
If the flashing piece is exposed to view and the design intent is that it have the same finish as the SF/CW I push hard for it to be provided by the SF?CW provider.
The specifier decides the appropriate location to specify things, so you have the final word. I would take the rep’s suggestion under advisement and do what you think is right.
The contractor has ultimate responsibility to provide everything shown or spec’d, and they also have the ability to assign it to the sub they choose.
I use the same approach to flashing you describe, and am not aware of any feedback.
My rule of thumb for this situation has always been that exposed flashings and trim in direct contact with curtain wall and storefront are fabricated from prefinished metal (typically aluminum) matching the curtain wall and storefront system. So I will typically include flashings and trim in those Sections. I’ve never had a curtain wall or storefront manufacturer object to this.