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E XXX-XX
Standard Practice for Preparing Masonry Heater Test-Fire Fuel Cribs and Kindling[1]
This document is not an ASTM standard; it is under consideration within an ASTM technical committee but has not received all approvals required to become an ASTM standard. It shall not be reproduced or circulated or quoted, in whole or in part, outside of ASTM committee activities except with the approval of the Chairman of the Committee having jurisdiction and the President of the Society. Copyright ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428. All Rights Reserved.
1. Scope
1.1 This practice contains procedures for preparing masonry heater fuel charges and kindling beds to be used for wood-fired masonry heater thermal performance, emissions, and safety testing purposes.
1.2 Values given in SI units are to be regarded as the standard. Inch/pound units may be rounded (see IEEE/ASTM SI-10). All dimensions are actual unless specifically stated otherwise.
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[2]
E 1602 Guide for Construction of Solid Fuel Burning Masonry Heaters
IEEE/ASTM SI-10 Standard for Use of the International System of Units (SI): The Modern Metric System
2.2 Other Standards:
Title 40 of the U.S. Code of Federal Regulations (CFR) Part 60, Subpart AAA[3]
3. Terminology
3.1 Definitions:
3.1.1 firebox, n—chamber in an appliance within which fuel charges are placed and burned.
3.1.2 masonry heater, n—wood-fired appliance meeting the requirements of Guide E 1602 and exempt from U.S. EPA Wood Heater regulation under Title 40 of the Code of Federal Regulations, Section AAA.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 firebox height (ht), n—vertical dimension measured from the firebox floor or from the top surface of an elevated grate to the horizontal plane that intersects and is perpendicular to the top edge at the highest point of the firebox opening through which fuel is loaded.
3.2.1.1 Discussion--If fuel is not intended to be placed at this prescribed firebox height, an alternative firebox height may be specified by the manufacturer or builder. Any alternative firebox height assigned by the manufacturer or builder shall be clearly and permanently indicated by markings and labeling in clear operator view while placing fuel in the firebox.
3.2.2 firebox volume, n--mathematical product of the firebox height and the usable hearth area.
3.2.2 firebox volume, n—the mathematical product of the firebox height and the useable hearth area. m3 (ft3).
3.2.3 primary horizontal hearth dimension (PHhd), n—for all hearth shapes, the primary horizontal hearth dimension is the longest horizontal straight line that can be drawn on the hearth within the space intended for fuel placement (see Appendix XI for examples).
3.2.3.1 If a fuel-elevating grate is used, the primary horizontal hearth dimension, PHhd, is the longest horizontal straight line that can be drawn across the upper-most horizontal plane of the grate at the level where fuel and kindling are placed for burning.
3.2.4 secondary horizontal hearth dimension (SHhd), n—for all hearth area shapes, and for fireboxes with or without fuel-elevating grates, the secondary horizontal hearth dimension is the longest horizontal straight line that can be drawn within the hearth area perpendicular to the primary horizontal hearth dimension (PHhd).
NOTE 1--For square and full-circle hearths, the secondary and longest horizontal firebox dimensions are equal.
3.2.5 Uusable Hhearth Aarea (Ahearth), n--largest projected horizontal plane of the firebox.
3.2.5.1 Discussion--The usable hearth area shall be calculated as the sum of all geometric areas in the largest projected horizontal plane within the firebox unless a smaller usable hearth area is physically defined (see Appendix XI for examples). For fireboxes with elevated grates, the usable hearth area shall be calculated as the largest projected horizontal area of the grate.
4. Significance and Use
4.1 This practice provides a reproducible, repeatable procedure for preparing fuel cribs for test firing masonry heaters. Fuel cribs and kindling prepared according to this practice can be used in other masonry heater test methods for thermal performance, safety, and emissions.
5. Equipment and Instrumentation
5.1 Scale, capable of measuring mass weight in increments of 0.05 kg (0.1 lb) and having a load capacity of 200 kg (440 lb).
5.2 Wood Moisture Meter, capable of measuring wood moisture in increments of 0.1 % dry basis and having a range from 5 % up to at least 30 % dry basis.
5.3 Linear-Measure Equipment, a standard-verified meter stick or tape measure capable of measuring increments of 2 mm (0.1 in.).
5.4 Oxygen Analyzer, capable of measuring flue gas oxygen concentration within 0.1 %.
5.5 Saw, equipped with all of the appropriate Occupational Safety and Health Administration(OSHA) safeguards for safely sawing long (1- to 5-m (3 to 16-ft)) pieces of 89- by 89-mm (3.5- by 3.5-in.) hard and soft wood lumber.
6. Procedure for Fuel Crib Preparation
6.1 Test Fuel—Test fuel shall be air dried Douglas fir or spruce. The wood species of all fuel pieces burned for a test shall be the same and shall be reported with the test results.
Test fuel pieces shall consist of 89- by 89-mm (3.5- by 3.5-in.) and 89- by 51-mm (3.5- by 2-in.) actual dimensioned lumber. The average moisture content of each piece of fuel, as measured at three locations on each piece (one each not closer than 7.6 mm (3.0 in.) from each end and one near the middle of the length), at a depth of 25 mm (1 in.), shall be in the range of 19 to 25 % dry basis (16 to 20 % wet basis).
NOTE 2--Most wood moisture meters measure in dry-basis percent. Verify the moisture meter specifications to confirm its moisture basis output measurement type.
6.2 Test Fuel Length
6.2.1Fireboxes Without Elevated Grates--The required length of all fuel pieces shall be determined using Eq 1 as follows:
Lfp = {0.707 - [0.203 × (SHhd/PHhd)]} × PHhd (1)
Where:
Lfp = fuel piece length, mm (ftin);
SHhd = the secondary horizontal hearth dimension, mm (in.ft); and
PHhd = the primary horizontal hearth dimension, mm (in.ft).
6.2.2 Fireboxes with Elevated Grates--If a fuel-elevating grate is used in the firebox, a fuel piece length shall be the shorter of 1.5 times the primary fuel-elevating grate dimension or Lfp.
6.3Fuel Crib Volume, Vf—The fuel crib volume, Vf, is the total amount of fuel contained in each fuel crib, excluding the kindling. This practice contains the procedure for preparing three fuel cribs. is
6.3.1 The fuel crib volume, Vf, shall be calculated using a loading factor of 0.20 m3 of wood fuel per m3 of firebox volume (0.20 ft3 per ft3) for the first 33.3 % of the firebox height and using a loading factor of 0.10 m3 of wood fuel per m3 (0.10 ft3 per ft3) of firebox volume above 33.3 % of the firebox height (see Appendix XI for example calculations).
Vf = (0.20 m3/m3)(0.333)(ht)(Ahearth) + (0.10 m3/m3)(0.667)(ht)(Ahearth) (2–SI)
Vf = (0.20 ft3/ft3)(0.333)(ht)(Ahearth) + (0.10 ft3/ft3)(0.667)(ht)(Ahearth) (2–inch- pound)
6.3.2 Elevated Grates--For fireboxes with elevated grates, the fuel crib volume, Vf, calculated by Eq 2 shall be multiplied by a factor of 1.5 but shall not exceed the fuel crib volume calculated using the usable hearth area without the grate.
6.4 Test Fuel Cribs—The test fuel pieces specified in 6.1-6.3 shall be constructed into fuel load “cribs” having multiple layers as needed to provide the fuel crib volume. A test fuel crib shall consist of at least two layers of fuel pieces. Three separate fuel load cribs shall be prepared as described in 6.5.16.4-6.6.using19- by 38-mm by 44 mm (0.75- by 1.5-in. by 1.75 in.) wood spacers centered between all fuel pieces. Spacer wood volume is excluded from fuel load volume calculations. Spacer weight is included and recorded for all total fuel weight measurements.
6.4.1 The overall horizontal fuel crib width (Hcw) shall be determined using Eq 3 as follows:
Hcw= {0.707 - [0.203 × (SHhd/PHhd)]} × SHhd (3)
Where:
Hcw = horizontal crib width, mm (in.ft);
SHhd = the secondary horizontal hearth dimension, mm (in.ft); and
PHhd = the primary horizontal hearth dimension, mm (in.ft).
6.4.1.1 First fuel load crib--Except as specified in 6.4.2, the bottom (first) layer of the first fuel load crib shall consist entirely of 89- by 51-mm (3.5- by 2.0-in.) fuel pieces nailed parallel to each other with 19-mm (0.75-in.) spacing between them and with their 89-mm (3.5-in.) sides positioned vertically. The second, third, and higher layers of the first fuel load crib shall consist entirely of 89- by 89-mm (3.5- by 3.5-in.) fuel pieces nailed together with spacers as specified in 6.6. See FIG 1.
6.4.1.2 Second and third fuel load cribs--Except as specified in 6.4.2, the second and third fuel load cribs shall consist entirely of 89- by 89-mm (3.5- by 3.5-in.) fuel pieces nailed parallel to each other with 19-mm (0.75-in.) spacing between them as shown in FIG 2. See 6.6 for wood spacer specifications and construction.
6.4.2 For fireboxes having a height of less than 305 mm (12 in.), the height of each fuel piece and all vertically positioned fuel crib spacers shall be reduced proportionally to the amount that the firebox height is less than 305 mm (12 in.).
6.4.2.1 For example, if a firebox has a height of 203 mm (8 in.), each piece of the fuel load and all vertical fuel piece spacers shall be reduced in height to [(203/305 mm) × 89 mm = 59.2 mm] [(8/12 in.) × 3.5 in. = 2.3 in.]. The unit volumes for all reduced fuel piece sizes shall be used in all subsequent calculations for determining the number of fuel pieces contained in each fuel load crib.
6.5 Determination of Fuel Crib Configuration
6.5.1 First Fuel Crib – The first fuel crib shall be made of a bottom/first layer containing the number of pieces calculated in Eq 4, plus one or more additional layers. The aggregate number of pieces used in the second and higher layers (Ntop) shall be determined in accordance with 6.5.1.2, with each layer having the number of pieces (n1,i) as specified in 6.5.1.3.
6.5.1.1 Bottom/first Layer—The number of pieces is the closest whole number result from Eq 4 as follows:
n1,1=[(Hcw × 1000 mm/m) + 1.9 mm0.19 cm]/70 mm7.0 cm (4–SI)
n1,1= [(Hcw × 12 in./ft) + 0.75 in.]/2.75 in. (4–inch-pound)
Where:Hcw = Horizontal crib width, cm (in.) from Eq. 3
NOTE 3--When the result is X.50, round up if the integer, X, is even and down if the integer, X, is odd.
6.5.1.2 Second and higher layers - The aggregate number of 89- by 89-mm (3.5- by 3.5-in.) upper-layer fuel pieces for the first fuel crib load is determined by the following three calculation steps.
NOTE 35--The unit volume, Vunit,1, of 89- by 51-mm (3.5- by 2.0-in.) dimensioned lumber is 0.004 54 m3/lineal m (0.0489 ft3/lineal ft) and the unit volume, Vunit,2, of 89- by 89-mm (3.5- by 3.5-in) dimensioned lumber is 0.007 92 m3/lineal m (0.0852 ft3/lineal ft).
6.5.1.2.1 Step 1TFFCblv = FFCblps x Lfp x BLFPuv
Vbot =n1,1 × Lfp × Vunit,1(5)
Where:
TFFCblv Vbot = total first fuel crib bottom layer fuel volume, m3 (ft3);
FFCblps n1,1 = number of first fuel crib bottom layer pieces (from Eq 4);
Lfp = length of each fuel crib piece, m (ft) from Eq 1; and
BLFPuv Vunit,1 = bottom layer fuel piece unit volume: 0.004 54 m3/lineal m (0.0489 ft3/lineal ft) (for bottom layer 89- by 51-mm piece).
6.5.1.2.2 Step 2FFCufptl = (TFCv – TFFCblv) / UFPuv
Ltop =(Vf - Vbot)/Vunit,2(6)
Where:
FFCufptl Ltop = total combined first fuel crib upper-layer piece length, m (ft);
TFCv Vf = fuel crib volume, m3 (ft3); from 5.3),
FFCblv Vbot= first fuel crib bottom layer volume, m3 (ft3); and from 5.4.3.1
UFPuv Vunit,2 = upper fuel-piece unit volume, 0.007 92 m3/lineal m (0.0852 ft3/lineal ft), and (for upper layer 89- by 89-mm piece).
6.5.1.2.3 Step 3
Ntop = Ltop/Lfp(7)
Where:
Ntop = aggregate number of first fuel crib upper-layer fuel pieces.
6.5.1.3 Pieces per Layer (other than bottom/first layer)--The aggregate number of fuel pieces in the second and higher layers (Ntop) as calculated in 6.5.1.2 shall be divided evenly into layers. The number of fuel pieces per layer, i, n1,i, is the closest whole number result from Eq 8 as follows:
n1,i = [(Hcw × 1000 mm/m) + 0.19 cm1.9 mm]/10.8 cm108 mm (8–SI)
n1,i = [(Hcw × 12 in./ft) + 0.75 in.]/4.25 in. (8–inch-pound)
Where:Hcw= Horizontal crib width, cm (in.) from Eq. 3
NOTE 4--Round up for X.50 results when the X integer is even and down for X.5 results when the X integer is odd.
6.5.2 Partial piece lengths calculated by Eq 6 that are less than 10 % of whole piece lengths shall be discarded and not used in fuel crib construction. Calculated partial piece lengths equal or greater than 10 % shall be cut to the calculated length and positioned at the top center of the whole fuel crib load. The size and weight of discarded pieces shall be recorded and reported with test results.
6.5.3 The ratio of the number of 89- by 89-mm (3.5- by 3.5-in.) fuel pieces in each of the second and higher layers to 89- by 51-mm (3.5- by 2.0-in.) fuel pieces in the bottom first layer shall be between 0.60 and 0.75.
6.5.4 Second and Third Fuel Cribs – The second and third fuel crib load are constructed entirely of 89- by 89-mm (3.5- by 3.5-in.) fuel pieces. The total number of pieces for each fuel crib load is determined by the following two calculation steps:
6.5.4.1 Step 1
L2 and 3= TFCv Vf/UFPuvVunit(9)
Where:
L2 and 3= total of all fuel crib piece lengths for each second and third fuel crib load, m (ft).
6.5.4.2 Step 2
N2 and 3 = L2 and 3/Lfp(10)
Where:
N2 and 3 = number of fuel crib fuel pieces in each fuel crib load.
6.5.4.3 Calculated partial second or third fuel crib piece lengths (L2 and 3)of less than 10 % of whole-piece lengths shall be discarded and not used in fuel crib construction. Calculated partial fuel crib pieces equal to or more than 10 % of the piece lengths shall be cut to the indicated partial-piece length and positioned at the top center of the whole fuel crib load. The size and weight of discarded ends shall be recorded and reported with test results.
6.6 Test Fuel Crib Construction—Testfuel cribs shall be constructed by nailing fuel pieces and spacers together with 18-gage by 32- mm (1¼-in.) finishing brads. Spacer wood shall be the same wood species as used for test fuel. Parallel fuel pieces shall be spaced 19 mm (0.75 in.) apart by nailing 19- by 38- by 89-mm (0.75- by 1.5- by 3.5-in.) spacers between all longitudinal fuel piece surfaces.The 19-mm (0.75-in.) spacing between the parallel fuel pieces shall be made by nailing, with 18-gage by 1¼-in. finishing brads19- by 38- by 89-mm (0.75- by 1.5- by 3.5-in.) spacers flush with each end and on alternating facing sides of each fuel piece. No spacers are to be attached to fuel piece surfaces facing outward from the fuel crib.
6.6.1 Spacing between fuel crib layers shall also be accomplished by nailing a piece of spacer wood (19 by 38mm (0.75 by 1.5in.)) equal in length to the secondary horizontal crib dimension, SHhd, to the bottom of the next highest crib layer, flush with each end., with 18-gage by 1¼-in. finishing brads, one See FIG 3. crib-depth (that is, the shortest horizontal crib dimension) of the 19- by 38-mm (0.75- by 1.5-in.) spacer wood flush with each end and on the bottom of each of the next highest crib layers. Maximum spacing between all fuel pieces shall not exceed 19 mm (0.75 in.). See FIGS 1 and 2.
6.6.2 Spacer weight shall be included and recorded for all total fuel weight measurements. Spacer wood volume shall be excluded from fuel load volume calculations.
6.6.3 If a fully constructed fuel crib cannot be safely loaded into the firebox or cannot fit through the test appliance’s fuel-loading door, whole fuel crib layers may be loaded separately starting with the lowest layer and placing subsequently higher layers on top of each other. Only in cases in which the entire fuel crib whole fuel crib layers cannot be placed in the firebox safely or cannot fit through the test appliance’s fuel-loading door can fuel crib layers be separated into smaller groups of fuel pieces or individual fuel pieces for loading. In any case, the fuel piece spacing and fuel crib layer and stacking configurations prescribed in this practice shall be maintained.
6.7 Fuel Crib and Piece Alignment For Testing--Kindling loads and test fuel crib pieces shall be aligned for fuel charging and recharging so that the lengths of the fuel pieces are parallel to the longest straight firebox wall in the hearth-floor or footprint plane of the firebox. For nonrectilinear firebox hearth shapes including those with more than four walls, those that have round or oval walls, or those with combinations of straight-line and curved hearth footprints, test fuel crib pieces shall be aligned for fuel charging and recharging so that the lengths of the fuel pieces are parallel with the line used for determining the primary horizontal hearth dimension (PHhd).
7. Procedure for Kindling Preparation
7.1 Kindling Preparation—For each test, a kindling bed or kindling stack shall be prepared for initiating test fire-burning periods. Kindling fuel shall consist of 19- by 19-mm (0.75- by 0.75-in.), 19- by 38- mm (0.75- by 1.5-in.), and 38- by 38 mm (1.5- by 1.5-in.) dimensioned lumber. The species and moisture content of the kindling fuel is not specified. The kindling fuel load weight is not part of the initial fuel crib load weight but is in addition to it and is used in calculating total fuel used during test periods.
7.2 Construction of Kindling Bed
7.2.1 For fireboxes with no fuel-elevatingwithout an elevated grate, the kindling bed shall consist of four layers of the specified kindling fuel pieces constructed or positioned as follows:
7.1.17.2.1.1 The first (bottom) layer shall consist of two equal length pieces of the 19- by 38-mm (0.75- by 1.5-in.) lumber cut to not more than 75 % but not less than 65 % of the secondary horizontal hearth dimension (SHhd). These two pieces are placed on their 19-mm (0.75-in.) edge on the floor of the hearth perpendicular to the longest straight firebox wall.
7.2.1.2 Discussion – For non-rectilinear firebox hearth shapes including those with more than four walls, those that have round or oval walls, or those with combinations of striagh-line and curved hearth shapes, first layer kindling pieces shall be aligned so that the kindling piece lengths are parallel with the line used for determining the primary horizontal hearth dimension (PHhd).
7.1.27.2.1.3 The second layer shall consist of two equal length pieces of the 19- by 38-mm (0.75- by 1.5-in.) lumber cut to 75 % but not less than 65 % of the primary horizontal hearth dimension, (PHhd), placed on their 19-mm (0.75-in.) edges, at the ends and on top of the two-piece first layer. The ends of the bottom two pieces are positioned so that the ends of all first- and second-layer pieces meet at the corners formed by the intersecting pieces.
7.1.37.2.1.4 Newspaper—Crumple one full double-tabloid-width newspaper page and place them with even spacing and no compression within the space created by the first two kindling bed layers.