ASTM C 1283-01

ASTM C 1283
Proposed Changes

8/30/01

ASTM C 1283
Standard Practice for Installing Clay Flue Lining

Summary:
Ballot Item 1 - Section 1.1 - Add "concrete" to allow for the use of concrete to build chimneys.
Ballot Item 2 - Section 1.1 - Eliminate height limit of chimneys to 40 ft. because it's too restrictive for the use of clay flue liners.
Ballot Item 3 - Section 2.1 - Change C 145 to C 1184 Standard Specification for Structural Silicone Sealants referrenced in Section 8 of the Standard because it was an incorrect referrence.
Ballot Item 4 - Section 3.1.1 - Add definition of Masonry Chimney to add clarity to the practice.
Ballot Item 5 - Section 3.1.2 - Add definition of Chimney Connector to add clarity to the practice.
Ballot Item 6 - Section 3.1.3 - Add definition of Flue Liner to add clarity to the practice.
Ballot Item 7 - Section 3.1.4 - Add definition of Flue to add clarity to the practice.
Ballot Item 8 - Section 3.1.5 - Add definition of Smoke Chamber to add clarity to the practice.
Ballot Item 9 - Section 3.1.6 - Add definition of Thimble to add clarity to the practice.
Ballot Item 10 - Section 4 - Add "footings" to be more coprehensive.
Ballot Item 11 - Section 4.1 - Recent code language on footings and foundations is both more clear and concise.
Editorial Change - Section 4.2 - The word "mutual" is redundant.
Ballot Item 12 - Section 4.3 - Eliminate and renumber rest of section. This language is vague and redundant.
Ballot Item 13 - Section 4.5.1 - Change "capacity" to "capability" as more appropriate and eliminate redundant language now in Section 4.1.
Ballot Item 14 - Section 5.1 - Add "and" or "or" where two or more standards are referrenced depending on whether a material must meet both standards or either standard to make it more clear.
Ballot Item 15 - Section 5.4 - Delete words "ahead of construction" to allow for relining existing chimneys. Change "linings" to "liners" to be consistent.
Ballot Item 16 - Section 5.5 - Remove the word "four" - inappropriate if the flue is round or oval.
Ballot Item 17 - Section 5.5 - Add the word "concrete" to allow for concrete chimneys.
Ballot Item 18 - Section 5.5 - Add phrase about not grouting flues in solid in seismic design areas to allow for thermal expansion.
Ballot Item 19 - Section 5.6 - Change "linings" to "liners" to be consistent.
Ballot Item 20 - Section 5.6 - Change language on slope to be more clear.
Ballot Item 21 - Section 5.9 - Change "connections" to "chimney connectors" to be consistent.
Ballot Item 22 - Section 5.10 - Add "concrete" or solid masonry to allow for concrete chimneys.
Ballot Item 23 - Section 5.10 - Delete 12" thickness requirement for stone chimneys as obsolete.
Ballot Item 24 - Section 5.10.1 - Add "concrete" to allow for concrete chimneys.
Ballot Item 25 - Section 5.10.1 - Allow hollow brick to be grouted solid so that cored brick can be used consistent with code.
Editorial Change - Section 5.12 - Makes more clear.
Ballot Item 26 - Section 5.13 - Add the word "centerline" in order to clarify from which point to measure.
Ballot Item 27 - Section 6.1 - Eliminate redundant language "the minimum shall be at least.."
Editorial Change - Section 6.3 - 30.5 should be 305 - typo.
Ballot Item 28 - Section 6.1 - 6.3 - Reorganize to bring into conformity with current building codes.
Ballot Item 29 - Section 6.4 - Add language to clarify intent of section.
Ballot Item 30 - Section 7.1 - Change "masonry" to "clay" to be more specific.
Ballot Item 31 - Section 7.1 - Change "be fed" to "drain" to make the language more clear.
Ballot Item 32 - Section 7.2 - Add language to clarify clearances around thimbles.
Ballot Item 33 - Section 7.3 - Eliminate ambiguous language.
Ballot Item 34 - Section 7.4 - Eliminate "specified" as redundant.
Ballot Item 35 - Section 8.0 - Eliminate "Terminations" as unnessessary.
Ballot Item 36 - Section 8.1 - Add "a minimum ten degrees" to specify a munimum slope
Ballot Item 37 - Section 8.2 - Change "at least" to "a minimum of".
Ballot Item 38 - Section 8.3.1 - combine and reorganize sections 8.3.1 through 8.3.8 to clarify the construction of chimney caps.
Ballot Item 39 - Section 9.1 - Changed wording to clarify section.
Ballot Item 40 - Section 9.1.1 - Changed wording to clarify section.

1. Scope
1.1 This practice covers the minimum requirements for installing clay flue lining for residential concrete or masonry chimneys ~~not exceeding 40 ft (12.2 m) in height~~.
1.2 The values stated in inch-pound units are to be regarded as the standard. The values stated in parentheses are for informational purposes only.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
C 24 Test Method for Pyrometric Cone Equivalent (PCE) of Fireclay and High Alumna Refractory Materials.
C 27 Standard Classification of Fireclay and High Alumna Refractory Brick
C 55 Standard Specification for Concrete Brick
C 90 Standard Specification for Loadbearing Concrete Masonry Units
C 99 Standard Test Method for Modulus of Rupture of Dimensional Stone
C 129 Standard Specification for Nonloadbearing Concrete Masonry Units
~~C 145 Specification for Solid Load-Bearing Concrete Masonry Units~~
C 170 Standard Test Method for Compressive Strength of Dimensional Stone
C 199 Standard Test Method for Pier Test for Refractory Mortars
C 216 Standard Specification for Facing Brick (Solid Masonry Units Made from Clay or Shale)
C 270 Standard Specification for Mortar for Unit Masonry
C 315 Standard Specification for Clay Flue Linings
C 652 Standard Specification for Hollow Brick (Hollow Masonry Units Made from Clay or Shale)
C 896 Standard Terminology Relating to Clay Products
C 1184 Standard Specification for Structural Silicone Sealants
3. Terminology
3.1 General - Terminology C 896 should be used for clarification of definitions in this practice.
3.1.1 Masonry Chimney - A vertical structure constructed of brick, concrete, concrete masonry units or stone which contains one or more flues and conveys products of combustion from a heat source or cooking appliance.
3.1.2 Chimney Connector - A tubular unit or pipe used to convey products of combustion from a heating or cooking appliance to the chimney.
3.1.3 Flue Liner - A manufactured tubular non-loadbearing fired clay unit , normally used for conveying hot gases in chimneys.
3.1.4 Flue - The passageway within a chimney through which products of combustion are conveyed.
3.1.5 Smoke Chamber - The section of a fireplace above the throat and below the flue which is an area of trasition from the shape of the throat to the shape of the flue.
3.1.6 Thimble - A manufactured tubular non-loadbearing fired clay unit normally used to connect the chimney connector from an appliance through the wall of the chimney to the flue.
4. Footings and Foundations
4.1 ~~The foundation shall be deep enough so that frost penetration and seasonal volumic changes in the soil will not affect its stability.~~ Footings for masonry chimneys shall be constructed of concrete or solid masonry at least 12 in. (305 mm) thick and shall extend at least 6 in. (153 mm) beyond the face of the foundation or support wall on all sides. Footings shall be founded on natural undisturbed earth or engineered fill below frost depth. In areas not subjected to freezing, footings shall be founded at least 12 in. (305 mm) below finished grade.
4.2 The foundation shall be placed, with respect to adjacent structures existing or anticipated, to minimize the possibility of ~~mutual~~ damage by construction operations or by transmission of additional loads to the supporting soils.
4.3 The foundation supports the chimney and shall be sized to carry all superimposed loads. Most building codes, however, disallow the use of chimney walls as structural elements to support other building components unless specific construction allowances are made. When designing the foundation, care shall be taken to account for soil types and conditions.
4.43 Concrete footings and foundations shall conform to local building codes.
4.43.1 In the absence of a local building code, concrete with a minimum 28 day compressive strength of 3000 psi (21 mPa) shall be used.
4.54 Where a chimney or fireplace is added to the outside of the exterior wall of an existing structure, the following shall apply:
4.54.1 The new footing shall be installed at the same level or below the existing footing, provided the level is below the frost line and the new footing is placed on soil with adequate bearing ~~capacity~~ capability. ~~In areas not subject to freezing, footings shall be at least 12 inches (305 mm) below finished grade.~~
4.54.2 The existing drainage provision shall not be obstructed.
5. Chimney Construction
5.1 Materials
5.1.1 Flue Linings - Specification C 315
5.1.2 Refractory Mortar - Test Method C 24, cone 5 and Test Method C 199.
5.1.3 Concrete Block - Specification C 90 or Specification C 129.
5.1.4 Brick - Specification C 55 or Specification C 216 Grade SW.
5.1.5 Mortar - Specification C 270.
5.1.6 Firebrick - Classification C 27.
5.1.7 Natural Stone - Test Method C 170 or Test Method C 99.
5.2 The chimney consists of a flue liner and the chimney wall. When used to vent a fireplace, the chimney is constructed directly on the smoke chamber.
5.3 The flue lining shall start from a point not less than 8 in. (205 mm) below the entrance of the lowest chimney connector.
5.4 Flue liners shall be installed ~~ahead of the construction of the chimney walls,~~ each flue liner carefully bedded on the previous one, using refractory mortar conforming to Test Method C 199. All joints of flue ~~linings~~ liners shall be 1/16 in. (1.5 mm) to 1/8 in. (3 mm) thick, and struck flush so as to produce a straight, smooth, fully aligned flue. Liners shall be placed in such a manner as to minimize ledges or steps within the flue passageway.
5.5 Flue liners shall be surrounded by masonry on all ~~four~~ sides but shall not be bonded to the surrounding masonry. The flue liner shall contact the chimney wall only as necessary for support and alignment in order to permit the flue liner, which when filled with hot gases and smoke to expand and contract freely. The separation of the flue liner from the surrounding concrete or masonry shall not exceed the wall thickness of the flue liner. ~~In seismic areas, local building codes for seismic zones may require additional anchoring or reinforcements.~~ Where Seismic Reinforcing requires the space between the flue liner and the chimney wall to be grouted solid the flue shall be wrapped with ceramic fiber paper capable of withstanding temperatures of 2100 deg. F to prevent the flue liner from bonding to the chimney walls.
5.6 The flue liner shall extend the entire height of the chimney. The ~~lining~~ liner shall be carried up as vertically as possible. When offsets are necessary, ~~the maximum slope shall be no greater~~ their slopes shall be no flatter than 30 degrees from vertical.
5.7 When more than one flue is contained in a chimney, a separation shall be provided between adjacent flues. The separation shall be solid masonry wythes (partitions) not less than 4 in. (102 mm) nominal thickness and bonded into the chimney walls.
5.8 Adjustments to the liner size or shape shall be made with a masonry saw.
5.9 Openings in the flue liner for ~~connections~~ chimney connectors shall be manufactured or machine cut.
5.10 Chimney walls shall be constructed of concrete or solid masonry units at least 4 in. (102 mm) nominal thickness. ~~Wall thickness of natural stone shall be 12 in (305 mm) minimum.~~
5.10.1 Products for chimney wall masonry construction are those (concrete, ~~block~~ concrete masonry units, brick or stone) that are ~~either 100% solid~~ at least 75% solid or grouted solid ~~or those~~ and which meet the requirements of Specification C 55, Specification ~~C 145~~ C90, Specification C 216 Grade SW, or Specification C652.
5.11 The chimney wall shall be adequately anchored to the building to provide stability against wind and seismic loads.
5.12 ~~All~~ The mortar in all joints exposed to weather shall be compacted and well tooled.
5.13 Masonry chimneys shall extend 3 ft (915 mm) above the highest point of the structure where chimneys pass through a roof of the building and at least 2 ft (610 mm) above any location of any structure within 10 ft (3 m) (measured horizontally from the vertical centerline chimney line).
6. Clearances
6.1 The minimum air space clearance between interior masonry chimneys and combustible materials shall be ~~at least~~ 2 in. (51 mm). Any chimney with at least one interior wall shall be treated as interior. When masonry chimneys are constructed as part of masonry walls or concrete walls, combustible materials shall not be placed in contact with the masonry wall within 12 in. (305 mm) of the inside surface of the flue liner.
6.2 The minimum air space clearance between exterior masonry chimneys and combustible materials shall be ~~at least~~ 1 in. (25 mm).
6.3 ~~Exposed combustible trim and the edges of sheathing materials, such as wood siding,~~ Combustible material shall be permitted to abut the masonry chimney sidewalls, provided such combustible trim or sheathing is a minimum of 12 in. (~~30.5~~ 305 mm) from the inside surface of the flue liner.
6.4 All spaces between chimneys and floors ~~and~~ or ceilings through which chimneys pass shall be fire stopped with non-combustible material. The fire stopping of spaces between chimneys and wood joists, beams or headers shall be galvanized steel not less than 26 gage in thickness or non combustible sheet material not more than 1/2 in. (13 mm) thick.
7. Openings For Chimney Connections
7.1 The chimney connection shall be made by either a metal or ~~masonry~~ clay thimble. The thimble shall be installed on a 1/4 in (6 mm) per foot slope toward the appliance. This is to allow any liquid creosote to ~~be fed~~ drain back into the appliance for reburning.
7.2 A minimum of 12 in. (305 mm) of solid masonry ~~separation~~ or a combination of 4 in. (102 mm) solid masonry and 2 in. (51 mm) air space shall be provided between clay thimbles and combustible materials.
7.3 The thimble shall pass through the flue lining and be flush with the inside of the flue lining ~~wall. In certain flue and thimble size combinations, it may be necessary to butt the thimble~~ or butted to the outside of the flue liner. The ~~area around the a clay thimble~~ joint between the thimble and the flue lining shall be sealed with refractory mortar.
7.4 The opening for a flue pipe connection shall be positioned to maintain the ~~specified~~ clearances from combustible construction, as specified in Section 6.
7.5 The stovepipe shall be positioned so that horizontal movement sill not cause it to back out of the thimble or protrude into the flue.
8. Chimney Caps ~~and Terminations~~
8.1 All masonry chimneys shall have a chimney cap that slopes a minimum 10 degrees downward from the flue liner to the edge of the chimney cap (see Fig. 1).
8.2 Chimney caps shall overhang the chimney wall by ~~at least~~ a minimum of 2 in. (51 mm)
8.3 Chimney caps are of the following types and construction:
8.3.1 Precast or cast-in-place concrete caps shall be a minimum of 2 in (51 mm) in thickness, shall have a drip slot on the underside at least 1-1/2 in. (38 mm) away from the chimney wall and shall be reinforced with a minimum of 1/2 in. (13 mm) mesh galvanized hardware cloth located halfway into the filled form..
~~8.3.2 Cast-in-place concrete.~~
8.3.32 Metal chimney caps must lap down the chimney wall at least 4 in. (102 mm) and a non combustible resilient sealant shall be used between the metal cap and the flue liner and between the base of the metal cap and the chimney.
8.3.43 Stone caps shall be a minimum of 2 in (51 mm) in thickness and shall have a drip slot on the underside at least 1-1/2 in. (38 mm) away from the chimney wall.
8.3.5 Precast, cast-in-place concrete, and stone chimney caps shall have a drip slot on the underside at least 1-1/2 in. (38 mm) away from the chimney wall.
8.3.6 Cast-in-place chimney caps shall be approximately 4 in. (102 mm) in thickness and reinforced with at least 1/2 in. (13 mm) mesh galvanized hardware cloth located halfway into the filled form.
8.3.7 Precast concrete and stone chimney caps shall be a minimum of 2 in (51 mm) in thickness. The cap shall fit loosely around the flue liner to permit expansion of the flue, but shall be sealed as specified in 8.4.
8.3.8 Metal chimney caps must lap down the chimney face at least 4 in. (102 mm) and a non combustible resilient sealant shall be used between the metal cap and the flue liner and between the base of the metal cap and the chimney.
8.4 Chimney caps shall be separated from the flue lining by a bond break, and this separation shall be sealed with a noncombustible resilient sealant to prevent water entering the chimney. This is a maintenance joint and should be checked and renewed as needed (see Fig 1).
8.5 Clay flue linings shall extend above the chimney cap by not more than 4 in. (102 mm).
9. Special Conditions
9.1 Special features to mitigate any problem relating to condensation shall be permitted in the construction of chimneys. ~~where condensation may occur.~~
9.1.1 Flue liners with joints that ~~provide improved characteristics for containing~~ prevent leakage of condensation shall be permitted. Socketed and overlapping joints manufactured as an integral part of the liner are acceptable.
9.1.2 A condensate drain installed at the base of the chimney shall be permitted.
10. Keywords
10.1 chimney; chimney caps; clay; fireplace; flue lining; masonry; stove pipe; venting.

Incorporating comments made by Editorial Committee ASTM C04.10, at October 9 and 24, 2001 meetings at Gladding McBean as recorded by Harvey Readers.
Ballot Item 1 - Section 1.1 - Add "concrete" to allow for the use of concrete to build chimneys.
Ballot Item 2 - Section 1.1 - Eliminate height limit of chimneys to 40 ft. because it's too restrictive for the use of clay flue liners.
Ballot Item 3 - Section 2.1 - Change C 145 to C 1184 Standard Specification for Structural Silicone Sealants referrenced in Section 8 of the Standard because it was an incorrect referrence.
Ballot Item 4 - Section 3.1.1 - Add definition of Masonry Chimney to add clarity to the practice.
Ballot Item 5 - Section 3.1.2 - Add definition of Chimney Connector to add clarity to the practice.
Ballot Item 6 - Section 3.1.3 - Add definition of Flue Liner to add clarity to the practice.
Ballot Item 7 - Section 3.1.4 - Add definition of Flue to add clarity to the practice.
Ballot Item 8 - Section 3.1.5 - Add definition of Smoke Chamber to add clarity to the practice.
Ballot Item 9 - Section 3.1.6 - Add definition of Thimble to add clarity to the practice.
Ballot Item 10 - Section 4 - Add "footings" to be more coprehensive.
Ballot Item 11 - Section 4.1 - Recent code language on footings and foundations is both more clear and concise.
Editorial Change - Section 4.2 - The word "mutual" is redundant.
Ballot Item 12 - Section 4.3 - Eliminate and renumber rest of section. This language is vague and redundant.
Ballot Item 13 - Section 4.5.1 - Change "capacity" to "capability" as more appropriate and eliminate redundant language now in Section 4.1.
Ballot Item 14 - Section 5.1 - Add "and" or "or" where two or more standards are referrenced depending on whether a material must meet both standards or either standard to make it more clear.
Ballot Item 15 - Section 5.4 - Delete words "ahead of construction" to allow for relining existing chimneys. Change "linings" to "liners" to be consistent.
C04.10 affirmative
Ballot Item 16 - Section 5.5 - Remove the word "four" - inappropriate if the flue is round or oval.
C04.10 affirmative
Ballot Item 17 - Section 5.5 - Add the word "concrete" to allow for concrete chimneys.
C04.10 affirmative with comment.
In the second sentence of the proposed rewrite of Section 4.1, I assume that in either case, undisturbed earth or engineered fill, the footing shall be below frost depth. The sentence should be modify to read, "Footings shall be founded below frost depth on natural undesturbed earth or engineered fill."
In the last sentence it is unclear as to where, base or the top of footing, the 12" is measured from.
In the proposed section all "inches" should be "in."
Ballot Item 18 - Section 5.5 - Add phrase about not grouting flues in solid in seismic design areas to allow for thermal expansion.
C04.10 affirmative
Ballot Item 19 - Section 5.6 - Change "linings" to "liners" to be consistent.
C04.10 affirmative with comment: See comments on Item 17.
Ballot Item 20 - Section 5.6 - Change language on slope to be more clear.
C04.10 affirmative with comment.
I am not involved with Building Codes, so perhaps "Seismic design categories" has some specific meaning. Except for this possibility, "seismic design" should suffice.
Continuing, though not a part of this ballot, there are several additional changes that I recommend.
a) In the first sentence of 5.5 referrence is made to "all four sides". There are oval and round flue liners - which do not have four sides. I suggest deleating the word "four". This then reads, in part, "surrounded by masonry on all sides.." This then is correct for all flue liner shapes.
Further in Section 5.6, last sentence it seems there is a redundancy (and possible confusion) by the use of "maximum slope" and "shall be no greater than 30 degrees from vertical". This provides the sense of maximum and minimum being similar and increasing numbers of degrees flattens the slope which is not desirable. The simple solution is to strike the word "maximum". Another possibility isto replace "greater" with "flatter", and leave "maximum" alone.
It seems that the last sentence of Section 5.5 is not appropriate in that location, in that there is no discussion of anchoring or reinforcement in 5.5. It seems that a better location would be in Section 5.11.
In Section 5.4, the copy submitted, but not that in the Book of Stnadards, calls for "1/18 in,". The value should be "1/16 in.".
In this same section 5.4 the first sentence says, "...on liner...to be bedded on the other..." This couls be interpreted, literally as only one needs to be bedded on another. Nonsensical, but that's what it says. I suggest tha "...each liner to be carefully bedded on the next..." [previous?]
Going bac to Section 5.5, again there is a discrepancy in wording between the Book of Standards copy and your submitted copy. If it is necessary to talk about "..hot gasses and smoke.." then your submitted copy is to be preferred, but regardless of the reason for expansion and contradiction, if we say "..to permit the flue liner to expand and contract freely.." it seems entirely clear. The hot gasses cause expansion and, if we concern ourselves with that, then we perhaps need to discuss the causes for contraction and truly seems excessive.
One last item, in your copy the word "gasses" should be "gases".
That seems belabored enough.
Ballot Item 21 - Section 5.9 - Change "connections" to "chimney connectors" to be consistent.
C04.10 affirmative with comment: Again "inches" should be "in.".
Ballot Item 22 - Section 5.10 - Add "concrete" or solid masonry to allow for concrete chimneys.
C04.10 affirmative with comment.
In the Action Item 22 submitted with the minutes the word "either"is present. In the submitted standard, "either" is struck out.
Ballot Item 23 - Section 5.10 - Delete 12" thickness requirement for stone chimneys as obsolete.
C04.10 affirmative. Editorial? [no]
Ballot Item 24 - Section 5.10.1 - Add "concrete" to allow for concrete chimneys.
C04.10 affirmative
Ballot Item 25 - Section 5.10.1 - Allow hollow brick to be grouted solid so that cored brick can be used consistent with code.
C04.10 affirmative - editorial
Editorial Change - Section 5.12 - Makes more clear.
Ballot Item 26 - Section 5.13 - Add the word "centerline" in order to clarify from which point to measure.
C04.10 affirmative with comment: Again "inches" should be "in.".
[This is the last comment in Harvey's notes, labeled "Action Items 16 through 27" which started with 15 and ends with 26. Were they completed and submitted? What about items 1 to 15 and from 27 to 40?]
Ballot Item 27 - Section 6.1 - Eliminate redundant language "the minimum shall be at least.."
Editorial Change - Section 6.3 - 30.5 should be 305 - typo.
Ballot Item 28 - Section 6.1 - 6.3 - Reorganize to bring into conformity with current building codes.
Ballot Item 29 - Section 6.4 - Add language to clarify intent of section.
Ballot Item 30 - Section 7.1 - Change "masonry" to "clay" to be more specific.
Ballot Item 31 - Section 7.1 - Change "be fed" to "drain" to make the language more clear.
Ballot Item 32 - Section 7.2 - Add language to clarify clearances around thimbles.
Ballot Item 33 - Section 7.3 - Eliminate ambiguous language.
Ballot Item 34 - Section 7.4 - Eliminate "specified" as redundant.
Ballot Item 35 - Section 8.0 - Eliminate "Terminations" as unnessessary.
Ballot Item 36 - Section 8.1 - Add "a minimum ten degrees" to specify a munimum slope
Ballot Item 37 - Section 8.2 - Change "at least" to "a minimum of".
Ballot Item 38 - Section 8.3.1 - combine and reorganize sections 8.3.1 through 8.3.8 to clarify the construction of chimney caps.
Ballot Item 39 - Section 9.1 - Changed wording to clarify section.
Ballot Item 40 - Section 9.1.1 - Changed wording to clarify section.

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