If more than one termination is located in the same chase or within the same general proxim- ity, we suggest they should be separated in distance at least 24" horizontally from flue center to flue center and stacked or staggered vertically at least 18" apart, from the termination of one smoke exit to the termination of another smoke exit (Figure 33 ).
This suggestion is provided in the interest of better operation. If the terminations are located too close to each other, smoke may migrate from one flue into the other.
CTD
18"
18"
CTDT 
CTDT
24"
24"
Figure 33
FTF10 CHIMNEY COMPONENT CALCULATIONS
The minimum installed height of the completed fireplace system is 15' 0". The maximum height is 60' 0".
To determine the number of chimney sections and chimney components required, follow these steps:
1.Determine total vertical height of the fire- place installation. This dimension is the dis- tance from the surface the fireplace sets on to the point where smoke exits from the termination.
2.Determine the number of chimney compo- nents required, except chimney sections. This would include firestop spacers, stabilizers, roof
flashing, etc.
3.The effective heights of the components are:
The Fireplace | = | 52" |
= | 10 ¹⁄₄" | |
= | 16 ¹⁄₄" | |
= | 34 ¹⁄₄" | |
= | 4" | |
= | 12" to 18" | |
= | 15" to 23" | |
= | 12" to 18" | |
= | 3"* |
*Required for every 30' of vertical chimney and/or 10' of offset chimney.
4.Determine amount of chimney height re- quired by subtracting total combined height of all
Reference Vertical Elevation Chart and determine the number of chimney sections (quantity and length) required.
SPECIAL OFFSET INSTRUCTIONSTo clear any overhead obstructions, you may offset your chimney system using Security Chimneys 30° offset and return elbows. Use two elbows - an offset elbow to initiate the offset and a return elbow to terminate it. A 30° offset elbow, angling in any direction, may be the first component used off the top of the fireplace flue collar.
The offset and return elbows may be attached together, or a section or sections of chimney may be used between, but do not exceed 20' in total length between elbows. If sections of pipe exceed 10' between elbows, a chimney stabilizer must be used at the midpoint (Figure 34 ). The stabilizer support straps must be attached under tension (in shear) to structural framing members above. When two sets of elbows are used, the maximum combined length of chimney used between elbows cannot exceed 20' (Figure 35 ). Example: If C1 = 10' then C2 cannot exceed 10'.
If an offset exceeds 6' in length, each chimney joint beyond the first 6' of offset to the return elbow, must be secured by a No. 8 x ¹⁄₂" sheet metal screw located at the underside of the joint (Figure 36 ).
NOTE: DIAGRAMS & ILLUSTRATIONS NOT TO SCALE.
A¹⁄₈" diameter hole must be drilled in the chimney joint using a ¹⁄₈" diameter drill. Hole should be drilled in center of joint overlap (Figure 37 ). Be sure to drill only through the outer chimney casting. Do not puncture the inner flue.
Maximum offset of chimney system is 30° . Two offsets must not be assembled to form a 60° offset. However, two sets of offset and return elbows may be used on a single flue system, provided the total height of the system exceeds 25'.
Return elbow support straps must be securely attached under tension (in shear) to structural framing members above. Do not substitute a
Step 1. Use Offset Chart to determine amount of horizontal offset (A) and height (B) for various chimney section assemblies.
Step 2. Use “Height of Chimney Only” column in The Vertical Elevation Chart to determine combinations of chimney used above return elbow to achieve desired heights. Reference Components Effective Height Chart in vertical elevation chart section.
Step 3. Use Elevation Chart as job estimator only. Add necessary firestop spacers and stabilizers as required. Firestop spacers must be used as shown in Figures 21 and 22 and stabilizers as shown in Figure 26.
A1
Return
Elbow
20'
Max.
B1
Stabilizer
10' Max.
Offset
Elbow
Figure 34
11