Got an RFI today pushing to drop top cover from 30 mm to 20 mm on a podium slab to fit sleeve congestion; per ACI 318 and our spec that compromises durability and fire resistance, so I’m holding for engineer direction. How are you documenting a firm no on site-driven tweaks like this without derailing a pour window, and do you keep a go‑to alternate detail (e.g., sleeve shift or bar swap) ready to offer?
Documented RFI: ‘no reduction in cover’; allowed 50 mm sleeve shift or small pourback boxes to save the pour.
I issue ‘no cover reduction’ per ACI 318, then core sleeves after pour — saves the window; flag firestopping early.
I keep a canned field directive: ‘no cover reduction per ACI 318,’ and swap in cast‑in firestop sleeves (e.g., Hilti CP 680: https://www.hilti.com/c/CLS_FIRESTOP_SYS_7131/CLS_CAST_IN_DEVICES_7131) or thinner‑wall/nonmetallic sleeves to shrink OD and keep the window. If that’s still tight, I use ACI 117 tolerances to drop the top mat a few millimeters and only list a post‑pour core as the backstop — helmet stays on, visor moves. Small caveat: if the slab carries the rating, a tiny local thickening beats touching cover.
@b_adams97 Agree on moving fast — what’s worked for me is a small soffit pocket with EPS under the sleeve so it drops clear and we keep top cover; I issue a quick sketch and we grout the pocket after inspection. If the slab is the rated element, use a cast‑in device instead (Hilti CID: https://www.hilti.com/c/CLS_FIRESTOP_SYS_7131/CLS_CAST_IN_DEVICES) to keep the window.