### Pellet Fuels Institute Standard Specificati on for Residential/Commercial Densified

Fuel

June 1, 2011

Page 1 of 10 Pellet Fuel Institute (PFI) Standard Specificatio n for Residential/Commercial Densified Fuel

1. Scope

1.1 This specification is applicable for the determ ination of fuel quality grade for Residential

or Commercial Densified Fu el as shown in Table 1.

1.2 Normative fuel properties included in the sp ecification are fines, bulk density, diameter, length, heating value, chloride, moisture c ontent, pellet durability index and inorganic

ash content. Determination of these properties is mandatory for determining fuel quality grade. Ash fusion is the only informative fu el property. Determination of ash fusion is not mandatory for determining fuel quality grade.

1.3 This specification is for the use of densified fuel produ cers to establish grade requirements for North American Residential/Com mercial densified fuel. It is also for the use of pellet fuel appliance manufactur ers for the purpose of designing appliances that meet air emission regulations that cite this standard specification and for users of

residential/commercial densifie d fuel in selection of the grade most suitable to their appliance.

1.4 Commercial users include commercial faci lities that utilize densified fuel burning appliances or equipment that have the same fuel requirements as residential appliances. Commercial applications shoul d not be confused with indus trial applications, which can utilize a much wider array of materials and have vastly different fuel requirements.

1.5 The values stated in inch-pound units are to be regarded as the st andard. Any values given in parentheses are mathematical convers ions to the International System of Units (SI units), which are provided for informati on only and are not considered standard. If values are stated in SI units only, they are to be regarded as the standard.

1.6 This standard specification 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 st andard specification to establish appropriate safety and health pract ices and to determine the applicability of regulatory limitations prior to use.

2. Referenced Documents 2.1 Pellet Fuels Institute (PFI) Program Standards:

2.1.1 PFI Residential/Commercial Densified Fuel QA/QC Handbook

2.2 ASTM Standards 1 : 2.2.1 ASTM E 873 Standard Test Method for Bulk Dens ity of Densified Particulate

Biomass Fuels.

2.2.2 ASTM E 871 Standard Test Method for Moisture Anal ysis of Particulate Wood Fuels

2.2.3 ASTM D 1102 Standard Test Method for Ash in Wood

2.2.4 ASTM E 791 Standard Test Method for Calculating Refuse-Derived Fuel Analysis Data from As-Determined to Different Bases

2.2.5 ASTM E 776 Standard Test Method for Forms of Ch lorine in Refuse-Derived Fuel

2.2.6 ASTM D 4208 Standard Test Method for Total Chlorine in Coal by the Oxygen Bomb

Combustion/Ion Selective Electrode Method

1. For referenced ASTM standards, visit the ASTM website, www.a stm.org, or contact ASTM Customer Service at service@astm.org.

### Pellet Fuels Institute Standard Specificati on for Residential/Commercial Densified

Fuel

June 1, 2011

Page 2 of 10 2.2.7 ASTM D 6721 Standard Test Method for Determinati on of Chlorine in Coal by Oxidative Hydrolysis Microcoulometry

2.2.8 ASTM E 711 Standard Test Method for Gross Calorifi c Value of Refuse-Derived Fuel by the Bomb Calorimeter

2.2.9 ASTM E 29 Standard Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications

2.2.10 ASTM C 702 Standard Practice for Reducing Samples of Aggregate to Testing Size

2.2.11 ASTM D 1857 Standard Test Method for Fusibi lity of Coal and Coke Ash

2.2.12 IEEE/ASTM SI10-2002 Standard for the Use of the Inte rnational System of Units (SI): The Modern Metric System

2.3 Other Referenced Documents:

2.3.1 Accreditation Body Residential/Commercial Densified Fuel Enforcement Regulations 2.3.2 Kansas State University - Mechanical Durability of F eed Pellets, Call Number:

LD2668 .T4 1962 Y68

3. Terminology

3.1 Definitions: General

3.1.1 bulk density – the fuel mass per cubic foot of the fuel sample

3.1.2 diameter – the average diameter of the fuel pellets in the fuel sample.

3.1.3 Pellet Durability Index (PDI) – a standardized parameter for specifying the ability of the fuel pellets to resist degrad ation caused by shipping and handling.

3.1.4 fines – the percentage of fuel material in the fuel sample passing through a 1/8 inch screen when the fuel is sampled in accordance with the requirements in 8.1.4

. 3.1.5 inorganic ash – the percent inorganic material in the fuel sample.

3.1.6 length – the weight percent of pellets exceed ing 1.5 inches in length in the fuel sample.

3.1.7 Moisture – the moisture content of the as-received fuel sample.

3.1.8 heating value – The higher heating value of the fuel sample.

3.1.9 NIST - The National Institute of Standard s and Technology (NIST) is a federal technology agency that develops and pr omotes measurement, standards, and technology.

### Pellet Fuels Institute Standard Specificati on for Residential/Commercial Densified

Fuel

June 1, 2011

Page 3 of 10 TABLE 1 PFI Fuel Grade Requirements

Table 1 Notes:

1. The following applies to all limits in this table: For purposes of determining the fuel grade, all properties must fall at or within the specified limits listed for a particular grade. Observed or

calculated values obtained from analysis shall be rounded to the nearest unit in the last righthand place of the figures used in expressing the limit in accordance with ASTM E 29 Standard Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications

. 2. It is the intent of these fu el grade requirements that fail ure to meet any fuel property requirement of a given grade does not automatically place a fuel in the next lower grade unless it meets all requirements of the lower grade. 3. There are no specific grade requirements fo r heating value, however densified fuel manufacturers must provide a minimum higher heating value guarantee on quality marked product when these standard specifications are used in conjunction with the PFI Residential/Commercial Densified Fuel QA/QC Handbook and the Accreditation Body Residential/Commercial Densified Fuel Enforcement Regulations . Quality marked product must also disclose the type of materials used as well as any additives as specified in section 8 of the

PFI Residential/Commercial De nsified Fuel QA/QC Handbook. Quality marked product must also exclude chemically treated materi als as specified in section 4.5 of the PFI Residential/Commercial Densified Fuel QA/QC Handbook. 4. NA – Not Applicable; No value

has been established.

### Pellet Fuels Institute Standard Specificati on for Residential/Commercial Densified

Fuel

June 1, 2011

Page 4 of 10 4. Detailed Requirements

4.1 The various grades of densified fuel shall conform to the limiting requirements shown in

Table 1.

5. Equipment and Supplies

5.1 Caliper – A vernier caliper capable of measur ing fuel diameter and length to within 0.001 in. (0.025 mm). Must meet the calibration requirements specified in 9.1

. 5.2 Analytical Balance – A balance with a resolu tion of 0.1 grams or bett er. Must meet the calibration requirements specified in 9.2

. 5.3 Measuring Block – A 1.5 inch (38 mm) long gauge block used for screening fuel pieces for length. Must meet the requirements specified in 9.3

. 5.4 Scale – A scale with resoluti on of 0.05 kilograms or better . Must meet the calibration requirements specified in 9.2.

5.5 Balance – A balance with a resolution of 0.01 kilograms or better. Must meet the calibration requirements specified in 9.2

6. Sampling and Sample Handling

6.1 The reader is strongly advised to review all intended test methods and sampling requirements prior to sampling in order to understand the importa nce and effects of sampling technique and special ha ndling required for each method.

7. Sample Preparation

7.1 A sample preparation schematic is shown in Annex B.1 to illustrate how a 40 lb bag of pelletized material should be subdivided to pe rform the analysis procedures. All sample subdividing shall be conducted ut ilizing a sample splitter with a slot width of 3.5 inches (89 mm) and meeting the require ments specified in ASTM C 702.

8. Test Methods

8.1 The requirements enumerated in this specifi cation shall be determined in accordance

with the referenced ASTM test methods or other referenced methods except where

modifications are noted or in accordan ce with the test procedures specified.

8.1.1 Bulk Density

– Determine in accordance with ASTM E 873 except this method shall

be revised to utilize a 1/4 cubic foot containe r that is tapped 25 tim es from 1 inch. In order to insure that an adequate sample qua ntity is available for this revised method, a minimum sample size of 12 pounds (5.44 kilograms) is recommended.

8.1.2 Diameter - Select 5 pellets randomly out of the pellet sample being evaluated and measure the diameter of each pellet with the calipe r specified in 5.1 . Each measured pellet diameter shall be recorded to th e nearest 0.001 inch. The average pellet diameter as well as the range of all pellet diameters measured shall be calculated and reported to the nearest 0.001 inch.

8.1.3 Pellet Durability Index (PDI) – Pellet durability shall be determined by using the method specified in Annex A.1

. It should be noted that th e pellets remaining after performing the fines determ ination as specified in 8.1.4 can be used without further preparation to conduct the durability test.

### Pellet Fuels Institute Standard Specificati on for Residential/Commercial Densified

Fuel

June 1, 2011

Page 5 of 10 8.1.4 Fines – Determined using the following procedur e that incorporates the use of a 1/8- inch (3.18 mm) wire screen sieve. All wei ght measurements shall be recorded to the nearest 0.1 gram.

8.1.4.1 Secure a representative fuel sample.

8.1.4.2 Reduce the sample size down to a minimum of 2.5 pounds (1,134 grams) using a sample splitter with 3.5-inch (89 mm) slots. Larger sample sizes may be used.

8.1.4.3 Using the analytical balance specified in 5.2 , weigh the sample and record as the initial sample weight to the nearest 0.1 grams.

8.1.4.4 Weigh the receiving pan and record the weight to the nearest 0.1 grams.

8.1.4.5 Attach a 1/8-inch (3.18 mm) screen to the receiving pan and place the pellet sample on the screen using care not to overload the screen. The maximum load on the screen should not exceed 1 pound (453 grams) of pellets per 100 square inches (645 square centimeters) of scr een surface area. Smaller screens may require the sample to be screened in increments.

8.1.4.6 Screen the sample by tilting the screen side to side 10 times.

8.1.4.7 If the sample is being screened in in crements, after the first portion has been

screened remove the 1/8-in ch (3.18 mm) screen from the base pan, and empty the pellets off the screen.

8.1.4.8 Repeat 8.1.4.5 through 8.1.4.7 until the entire sample has been screened.

8.1.4.9 Remove the 1/8-inch (3.18 mm) screen a nd weigh and record the weight of the base pan with the fines to the nearest 0.1 grams.

8.1.4.10 Calculate and report the pe rcent of fines to the nearest 0.01% as follows:

% Fines = [(Weight of Base Pan + Fines) – (Weight of Base Pan) ] x 100 Initial Sample Weight

8.1.5 An alternative fines determinati on procedure is provided in Annex C.1.

8.1.6 Inorganic As h – Determine in accordance with ASTM D 1102.

8.1.7 Length - Starting with 2.5 pounds (1.13 kilograms) of pellets randomly selected from the sample being evaluated, hand sort to identify pellets over 1.50 inches (38 mm) in length. Use the caliper specified in 5.1 or a certified measuring block as specified in

5.3 to confirm that a pellet exceeds the speci fied length. The weight percent of all pellets exceeding the specified length shall be reported. In addition, of the pellets exceeding the specified length, the longest pe llet shall be identified, measured with the caliper specified in 5.1 , and the length reported as the maximum pellet length.

8.1.8 Moisture – Determine in accordance with ASTM E 871.

8.1.9 Chloride – Determine in accordance with ASTM E 776 or ASTM D 4208 or ASTM

D 6721.

8.1.10 Ash Fusion - Determine in accordance with ASTM D1857.

8.1.11 Heating Value – Determine in accordance with ASTM E 711.

9. Calibration and Standardization

9.1 Caliper – Before each test, audit the calip er by measuring one NIST traceable gauge block that corresponds to between 80 percen t and 120 percent of the anticipated fuel diameter and by measuring the length of the measuring block specified in 5.3 . If the

### Pellet Fuels Institute Standard Specificati on for Residential/Commercial Densified

Fuel

June 1, 2011

Page 6 of 10 caliper can not reproduce the calibration gauge dimensions within 1%, the caliper may

not be used.

9.2 Balances and Scales - Perform an initial calibration using NIST or other recognized

national standards in accordance with the ma nufacturer’s instructions. Before each test, verify the balance or scale by using at least one calibration weight that corresponds to 50 to 150 percent of the weight of the fuel sample to be measured. If the balance or scale cannot reproduce the value of the calibration weight to within 1% of the mass,

recalibrate before use.

9.3 Measuring Block – The length of the block mu st be traceable to NIST and demonstrate accuracy of ±0.01 in. from length specified in 5.3 . The block manufactur er’s certification documents are sufficient for this purpose.

### Pellet Fuels Institute Standard Specificati on for Residential/Commercial Densified

Fuel

June 1, 2011

Page 7 of 10 Annex A.1

Pellet Fuels Institute Standard Operating Procedure for: Durability Testing – Residential/Commercial Pellet Fuels

Produced by: PFI Standards Committee

The Pellet Fuels Institute has adopted the test procedure outlined by Kansas State University (See Kansas State University - Mechanical Durability of Feed Pellets, Call Number: LD2668 .T4 1962 Y68) for assessing the durability of residential/commercia l densified fuel products, with the exception that the screen size used in determining durability has been modified to be a 1/8-inch (3.17 mm) wi re screen sieve.

The durability tester consists of a dust tight box. The box shall be made of a rigid material with smooth and flat surfaces (e.g., stai nless steel plate). The inner dimensions of the box shall be 305 ± 3 mm long by 140 ± 3 mm wide by 305 ± 3 mm deep. It shall rotate about an axis which is perpendicular to and centered in the nom inal 305 mm by 305 mm si des. A 230 ±3 mm long baffle is affixed symmetrically to a diagonal of one nominal 305 mm by 305 mm side of the box.

The baffle extends 50 ± 1 mm into the box and is s ecurely fastened to the back of the box. The edges of the baffle shall not be sharp, but rounded to avoid any cutting effect. A door may be placed on any side of the box. Projections, such as rivets and screws, shall be kept to a minimum and well rounded (alternatively, flat head screws ma y be used). An illustration of the tester is shown in Fig 1.

The procedure is outlined as follows:

1. Secure a representative pellet fuel sample . The minimum recommended representative sample weight is 1100 grams.

2. Screen the representative sample with a 1/8- inch (3.18 mm) wire screen sieve to remove fines. Obtain the initial test sample from the portion of the representative sample retained

on the screen.

3. Using the analytical balance specified in 5.2, weigh 500 ± 10 grams of the initial test sample and record as the initial we ight to the nearest 0.1 grams (IW).

4. Tumble the pre-weighed initial test sample in the durability tester at 50 ± 2 rotations per

minute for a total of 500 rotations.

5. Re-screen the tumbled test sample weigh th e portion retained on the 1/8-inch (3.18 mm)

sieve and record as the whol e pellet sample weight to the nearest 0.1 grams (WPW).

### Pellet Fuels Institute Standard Specificati on for Residential/Commercial Densified

Fuel

June 1, 2011

Page 8 of 10 6. Compute Pellet Durability Index (PDI) by di viding the whole pellet sample weight (WPW) by the initial weight (IW) of the sample and multiply by 100. Report to one decimal place.

PDI = 100 X WPW

IW

7. Repeat steps 2-6 on a second portion of the representative fuel sample.

### Pellet Fuels Institute Standard Specificati on for Residential/Commercial Densified

Fuel

June 1, 2011

Page 9 of 10

### Pellet Fuels Institute Standard Specificati on for Residential/Commercial Densified

Fuel

June 1, 2011

Page 10 of 10 Annex C.1


### Pellet Fuels Institute Alternative Fines Testing Procedure

Produced by: PFI Standards Committee

As part of this standard speci fication PFI has developed a sta ndard testing procedure for the determination of fines in a sample of densified fuel. The standard testing procedure is outlined in Section 6.1.4. The standard test procedure call s for a sub-sample to be taken from a 40 lb bag of pellets by means of a sample splitting device. This alternative testing procedure is offered as a comparable alternative to the st andard testing procedure and is intended for use when it is desired to determine the pe rcentage of fines in a 40 pound bag of densified fuel.

Using a Lucas Welding and Fabrication (270- 579-2114) Pellet Speed ScreenerTM (apparatus consists of a screener, a flanged cubic foot st eel container, and a fines collection cup), the following steps shall be followed to determine th e percent fines in a 40 pound bag of densified

fuel:

1. Secure a 40 pound bag of densified fuel.

2. Using the scale specified in 5.4, weigh the sample with the bag a nd record the initial weight to the nearest 0.05 kilograms (IW).

3. Pre-weigh the fines collection cup and record the weight to the nearest 0.01 kilograms (CW).

4. Assure the screener is clean, the flanged 1 cubic foot steel container is in place at the bottom of the screener, and the fine s collection cup is in its holder.

5. Turn on the table vibrator.

6. Pour the contents of the 40 pound bag of densif ied fuel into the hopper at the top of the table assuring all material is out of the bag.

7. Weigh the bag and record to th e nearest 0.01 kilograms (BW).

8. When the hopper is empty and all material has migrated to either the flanged 1 cubic foot

steel container or the fines collectio n cup, turn off the table vibrator.

9. Weigh the fines collection cup w ith the fines and record the weight to the nearest 0.01 kilograms (CFW).

10. Calculate the percentage of fines in the sample.

% Fines = (CFW – CW) / (IW – BW) x 100