Installing the Firestop Spacer
in the Ceiling Hole
A firestop spacer is used to keep pipe spaced properly and required for safety.
Nail the firestop spacer (at each corner) to the framing members of the ceiling hole. NOTE: A firestop spacer is not required at the roof.
Hole sizes listed in Figure 9 for angled firestop spacers provide minimum required air space to chimney pipe for ceiling thickness up to 8” (203 mm). When combined thickness of ceiling material, ceiling joists and flooring material exceeds 8” (203 mm), adjustments must be made in framing to assure that minimum air spaces to
chimney are maintained.
Proper Firestop Spacer Installation
Figure 18 shows different installation procedures for both an area that is an attic and an area that is not an attic.
If the area above the ceiling is not an attic, position the firestop spacer with the flange on the ceiling side and the angled portion extending up into the hole.
If the area above the ceiling is an attic, position the firestop spacer with the flange on the top of the framed hole and the angled portion extending down into the hole.
Firestop spacers are not available for, nor are they required on vertical walls.
DO NOT put any sealant around the area where the outer pipe slides through the firestop spacer. If you seal this area, it may cause a fire hazard.
Attic Installation 
Nails (4)
Firestop Spacer
Joist
NOTE: If the attic insulation shield is used, the firestop is not required in the attic installation.
Ceiling Installation
Joist
Firestop Spacer
Nails (4) | FP593 |
Fig. 18 Firestop spacer installations.
Vermont Castings EWF36A
Canadian Requirements
for Insulation Shield
In Canada, an attic insulation shield is required to prevent attic insulaiton from contacxting the chimney section. NOTE: If the attic insulation shield is used, the firestop is not required in the attic installation. Framing dimensions fr the chimney hole should measure 17¹⁄₂” x 17¹⁄₂” (445 x 445 mm). An attic shield MUST be installed on top of attic joists (above the floor level). (Fig. 19)
NOTE: In the U.S., it is a good idea, although not al- ways required, to install an attic insulation shield where
Attic Insulation
Shield
Nails
(4 Required)
| Attic Joist |
| Base |
Ceiling | Flanges |
FP263 |
Fig. 19 Attic shield installation (Canadian requirement).
Continue Installing Pipe to Complete Run
Continue attaching pipe sections to complete system to next level always being careful that the pipe is firmly snapped locked in place before proceeding to next pipe section.
Chimney Supports
If chimney supports are required, they are installed the same as elbows. Nail chimney support straps to adja- cent structural framing, as shown on Figure 16. Bend straps as necessary and make sure they are secure so they will support the weight of the chimney. A chimney support is 2¹⁄₂" (64 mm) long when installed. Consider this dimension when determining how many straight chimney sections are needed.
NOTE: Chimney supports are generally used in long runs in a chase installation.
Additional Ceilings
If you encounter additional ceilings, repeat same steps required for first ceiling installation. See firestop illustra- tion in Figure 18.
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