Waste paper grades are standardized classifications for recycled paper based on fiber type, contamination levels, and intended application. The two primary international systems—EN 643 (European) and ISRI (North American)—define specifications that determine pricing, quality expectations, and suitable end products for each grade.
With over 50% of global paper production now utilizing recycled fiber, understanding waste paper grades has become essential for mill profitability and product quality. Recycled fiber accounts for 35-60% of furnish in many paper grades, and global recovered paper utilization exceeds 250 million tonnes annually.
Selecting the right waste paper grades directly impacts production costs, machine runnability, and final product specifications. This comprehensive guide covers international classification systems, detailed specifications for each grade category, contamination management, and practical guidance for blending recycled fiber with virgin pulp.
What Are Waste Paper Classification Systems?
Two primary standards govern international waste paper trade: the European EN 643 standard and the North American ISRI specifications. Understanding both systems is essential for mills sourcing fiber globally.
EN 643 European Standard
The European List of Standard Grades of Paper and Board for Recycling (EN 643) was developed by CEPI (Confederation of European Paper Industries) and ERPA (European Recovered Paper Association). The current revision dates to 2014 and includes over 95 individual grades organized into five main groups.
| Group | Category | Primary Grades | Typical Applications |
|---|---|---|---|
| 1 | Ordinary grades | Mixed papers, OCC | Packaging, boards |
| 2 | Medium grades | Newspapers, magazines | Newsprint, tissue (deinked) |
| 3 | High grades | Printing/writing papers | Office papers, premium tissue |
| 4 | Kraft grades | Unbleached kraft papers | Kraftliner, sack paper |
| 5 | Special grades | Liquid packaging, coated boards | Specialty applications |
A significant feature of EN 643 is the introduction of maximum tolerance levels for non-paper components (1.5% for most grades) and grade-specific limits for unwanted materials.
ISRI Paper Stock Specifications
The Recycled Materials Association (ReMA, formerly ISRI) publishes the Scrap Specifications Circular, updated in 2024. This North American standard defines grades using numerical designations and specifies limits for prohibitives (materials that render a load unacceptable) and outthrows (materials requiring removal before processing).
| ISRI Grade | Name | EN 643 Equivalent |
|---|---|---|
| Grade 11 | OCC | 1.05 |
| Grade 12 | DS OCC | 1.06 |
| Grade 7 | ONP Regular | 2.01 |
| Grade 8 | ONP Special | 2.01 |
| Grade 10 | OMG | 2.06 |
| Grade 37 | SWL | 3.05 |
| Grade 40 | SOP | 3.01 |
What Are Group 1: Ordinary Grades (Mixed Papers and OCC)?
Group 1 represents the highest-volume waste paper grades, dominated by old corrugated containers (OCC) and mixed papers. These grades form the backbone of recycled packaging production globally.
Grade 1.01 - Mixed Paper and Board (Unsorted)
This lowest-tier grade consists of various paper and board types collected without sorting. Mills accepting this grade must invest heavily in stock preparation systems to remove contaminants.
- Non-paper components: Maximum 2%
- Unwanted materials: Maximum 40%
- Typical yield: 70-80%
- Applications: Chipboard, construction paper, low-grade recycled boards
Grade 1.02 - Mixed Paper and Board (Sorted)
A step above unsorted mixed paper, this grade undergoes basic sorting to remove obvious contaminants and limit newspaper/magazine content.
- Non-paper components: Maximum 1.5%
- Unwanted materials: Maximum 20%
- Newspaper/magazine content: Maximum 40%
- Applications: Recycled liner, folding boxboard middle layer
Grade 1.04 - Supermarket Corrugated
Collected primarily from retail establishments, this grade offers cleaner corrugated material than general OCC streams.
| Sub-grade | Corrugated Content | Non-Paper Max | Unwanted Max |
|---|---|---|---|
| 1.04.00 | Minimum 70% | 1.5% | 5% |
| 1.04.01 | Minimum 70% | 1.5% | 5% |
| 1.04.02 | Minimum 80% | 1.5% | 3% |
Grade 1.05 - Old Corrugated Containers (OCC)
OCC represents the single largest waste paper grade by global trading volume. This grade consists of used corrugated boxes and sheets, serving as the primary raw material for testliner and fluting production.
- Non-paper components: Maximum 1.5%
- Unwanted materials: Maximum 2.5%
- Other packaging allowed: 5-10% depending on sub-grade
- Applications: Testliner, fluting medium, kraft liner supplement
ISRI OCC Specifications:
| Grade | Description | Outthrows Max | Prohibitives Max |
|---|---|---|---|
| OCC 11 | Standard | 5% | Included in outthrows |
| DS OCC 12 | Double-sorted | 2% | 0.5-1% |
| OCC 95/5 | Premium | 5% | 95% OCC minimum |
| OCC 98/2 | Super premium | 2% | 98% OCC minimum |
Grade 1.06 - Sorted OCC
The premium OCC grade features stricter contamination limits and commands higher prices.
- Non-paper components: Maximum 1%
- Unwanted materials: Maximum 2%
- Applications: Premium testliner, high-quality fluting
What Are Group 2: Medium Grades (Newspapers and Magazines)?
Group 2 grades are primarily intended for deinking operations producing recycled newsprint, tissue, and printing papers. Fiber quality and deinkability are critical selection factors.
Grade 2.01 - Newspapers (ONP)
Old newspapers represent the primary feedstock for deinked pulp production. Quality requirements include freshness (not sunburned) and dryness.
- Non-paper components: Maximum 0.5%
- Unwanted materials: Maximum 1%
- Deinkability: Excellent
- Achievable brightness: 58-65%
- Applications: Newsprint, tissue, packaging (after deinking)
Grade 2.02 - Newspapers and Magazines
This mixed deinking grade combines ONP with old magazines (OMG), requiring adjusted deinking chemistry to handle coated papers.
- Coated paper content: Maximum 50%
- Achievable brightness: 55-62%
- Applications: Newsprint, SC paper, recycled tissue
Grade 2.05 - Sorted Graphic Paper for Deinking
Premium deinking feedstock sorted specifically for high-brightness recycled paper production.
- Non-paper components: Maximum 1%
- Achievable brightness: 75-85%
- Applications: Woodfree printing papers, office papers
Grade 2.06 - Magazines (OMG)
| Parameter | Specification |
|---|---|
| Coated paper content | Minimum 60% |
| Non-paper components | Maximum 1% |
| Achievable brightness | 60-70% |
| ISRI equivalent | Grade #10 |
What Are Group 3: High Grades (Printing and Writing Papers)?
High grades command premium prices due to their superior fiber quality, brightness potential, and low contamination levels. These grades are essential for producing recycled office papers and premium tissue.
Grade Specifications Comparison
| Grade | Description | Non-Paper Max | Price Index |
|---|---|---|---|
| 3.05 | White woodfree shavings | 0.25% | 100 (baseline) |
| 3.10 | White woodfree cuttings (printed) | 0.5% | 85-90 |
| 3.14 | White continuous stationery | 0.5% | 80-85 |
| 3.07 | White woodfree books | 0.5% | 80-85 |
| 3.01 | Mixed lightly colored shavings | 1.0% | 70-75 |
Grade 3.05 - White Woodfree Shavings
The highest-value recovered paper grade consists of unprinted, groundwood-free white paper shavings and cuttings.
- Source: Printing plants, converters
- Non-paper components: Maximum 0.25%
- Applications: Premium writing papers, facial tissue
- ISRI equivalent: Hard White Shavings (HWS)
ISRI High Grade Equivalents
| ISRI Grade | Name | Prohibitives Max | Key Characteristics |
|---|---|---|---|
| SWL (37) | Sorted White Ledger | 0.5% | No colors, no carbons |
| SOP (40) | Sorted Office Paper | 1% | Mixed office waste |
| HWS | Hard White Shavings | 0.5% | Unprinted cuttings |
| MWL | Manifold White Ledger | 0.5% | Industrial waste |
What Are Group 4: Kraft Grades?
Kraft grades contain long softwood fibers providing superior strength properties. Limited availability and high demand result in premium pricing.
| Grade | Description | Applications |
|---|---|---|
| 4.01 | New corrugated kraft | Premium kraftliner, sack kraft |
| 4.03 | Used kraft sacks | Kraftliner (contamination risk) |
| 4.04 | Unused kraft sacks | Sack kraft, premium kraftliner |
| 4.06 | New kraft cuttings | High-strength packaging |
Key Characteristics
- Fiber type: Long softwood kraft (2.5-4.0 mm)
- Strength contribution: Excellent tear and tensile
- Availability: Limited compared to OCC
- Pricing: Premium (approaching virgin kraft values)
- Contamination concerns: Used sacks may contain cement, food residues
What Are Group 5: Special Grades?
Special grades require specialized processing equipment and present unique challenges for recyclers.
Grade 5.01 - Liquid Packaging Board
Beverage cartons (Tetra Pak, juice cartons, milk cartons) contain valuable fiber but require separation from plastic and aluminum layers using specialized pulper equipment.
| Component | Percentage | Recovery Method |
|---|---|---|
| Fiber | 70-75% | Hydrapulping |
| Polyethylene | 20-22% | Separation, energy recovery |
| Aluminum | 3-5% | Separation, recycling |
Grade 5.03 - Wet Strength Papers
Papers containing wet strength resins (polyamide epichlorohydrin, glyoxalated PAM) resist water dispersion and require extended pulping times with chemical treatment.
- Processing time: 2-4x standard pulping
- Chemical requirements: Hypochlorite or enzyme treatment
- Applications: Often limited to energy recovery
Grade 5.07 - Labels and Adhesive Papers
Self-adhesive papers represent a major source of stickies contamination. Specialized processing with aggressive screening and flotation is required.
What Contamination Types and Tolerance Limits Apply?
Contamination management is critical for machine runnability and product quality. Understanding contamination categories helps mills establish effective quality control programs.
Prohibited Materials (Zero Tolerance)
These materials must never enter the waste paper stream:
- Medical and hygiene waste
- Hazardous materials (batteries, chemicals, paint)
- Food waste causing wet contamination
- Bitumen/asphalt-coated papers
- Carbon paper (most grades)
- Sanitary products
Non-Paper Components
| Component | Typical Limit | Impact | Removal Method |
|---|---|---|---|
| Plastics | 1-2% | Wire/felt plugging | Screening, cleaning |
| Metals | 1-2% | Equipment damage | Magnets, HD cleaners |
| Glass | <0.5% | Abrasive wear | HD cleaners |
| Textiles | <0.5% | Wire blinding | Coarse screening |
| Sand/dirt | <1% | Wear, spots | Centri-cleaners |
Stickies: The Most Problematic Contaminants
Stickies cause machine deposits, felt plugging, and sheet defects. Understanding their sources enables better incoming material control.
| Sticky Type | Source | Behavior | Removal Method |
|---|---|---|---|
| Hot melts | Book bindings, case sealing | Soften at 50-80°C | Flotation, fine screens |
| Pressure-sensitive | Labels, tapes, post-its | Tacky at room temp | Dispersion, screening |
| Wax | Coatings, some hot melts | Melt at 50-70°C | DAF, cleaning |
| Latex | Paper coatings | Soften during processing | Flotation, cleaning |
Chemical Composition of Stickies:
- Polyvinyl acetate (PVA)
- Styrene butadiene rubber (SBR)
- Ethylene vinyl acetate (EVA)
- Paraffin waxes
Moisture Specifications
| Moisture Level | Status | Issues |
|---|---|---|
| 8-12% | Optimal | Standard trading moisture |
| >15% | Too wet | Weight fraud risk, mold growth |
| <6% | Too dry | Dust problems, pulping difficulties |
How to Blend Waste Paper with Virgin Fiber?
Recycled fibers experience quality degradation through repeated processing cycles. Strategic blending with virgin fiber compensates for these limitations while optimizing costs.
Why Blend?
- Compensate for hornification - Recycled fibers lose bonding ability
- Meet strength specifications - Virgin fiber provides tensile and tear
- Optimize costs - Balance quality requirements with material costs
- Achieve sustainability targets - Maximize recycled content within quality limits
Typical Blend Ratios by Product
| Product | Virgin Fiber | Recycled Fiber | Preferred Grades | Critical Property |
|---|---|---|---|---|
| Newsprint | 0-30% | 70-100% | ONP/OMG deinked | Brightness |
| Testliner | 0-20% | 80-100% | OCC | Cleanliness |
| Kraftliner | 60-100% | 0-40% | OCC, kraft grades | Strength |
| Fluting | 0-30% | 70-100% | OCC, mixed | CMT, SCT |
| Recycled tissue | 0-30% | 70-100% | Deinked pulp | Brightness, softness |
| Writing paper | 50-80% | 20-50% | High grades only | Brightness |
| Folding boxboard | 30-50% | 50-70% | Mixed grades | Layered properties |
Fiber Property Comparison
| Property | Virgin Softwood | Virgin Hardwood | Recycled (OCC) | Recycled (Deinked) |
|---|---|---|---|---|
| Fiber length | 2.5-4.0 mm | 0.8-1.2 mm | 1.0-2.0 mm | 0.8-1.5 mm |
| Freeness (CSF) | 650-720 mL | 450-550 mL | 300-450 mL | 350-500 mL |
| Bonding ability | Excellent | Good | Fair | Fair-Good |
| Tear contribution | Excellent | Poor | Fair | Poor-Fair |
Hornification and Recycling Limits
Hornification refers to the irreversible stiffening and collapse of fiber structure during drying cycles. This phenomenon limits effective paper recycling to 5-7 cycles.
| Recycling Cycle | Property Retention | Notes |
|---|---|---|
| 1st cycle | 70-85% | Greatest degradation |
| 2nd cycle | 85-90% of previous | Slower decline |
| 3rd-4th cycle | 90-95% of previous | Leveling off |
| 5th-7th cycle | Near plateau | Fiber approaching limit |
Mitigation strategies:
- Virgin fiber addition: 15-25% of furnish
- Refining (limited benefit due to already shortened fibers)
- Enzyme treatments to restore fiber swelling
- Chemical swelling agents
How to Select Grades by End Product?
Selecting appropriate waste paper grades requires matching fiber properties to product specifications.
Packaging Grade Selection
| End Product | Preferred Grades | Alternative Grades | Key Quality Factor |
|---|---|---|---|
| Kraftliner | 4.01, 4.04 | 1.05 (with virgin blend) | Strength |
| Testliner | 1.05, 1.06 | 1.04 | Cleanliness |
| Fluting medium | 1.04, 1.05 | 1.02 | CMT, SCT values |
| Chipboard | 1.01, 1.02 | Any mixed | Cost optimization |
Printing/Writing Paper Selection
| End Product | Preferred Grades | Key Quality Factor |
|---|---|---|
| Woodfree offset | 3.05, 3.10 | Brightness, cleanliness |
| Newsprint | 2.01, 2.02 | Deinkability |
| SC paper | 2.02, 2.06 | Smoothness, brightness |
Tissue Grade Selection
| End Product | Preferred Grades | Key Quality Factor |
|---|---|---|
| Premium (virgin equivalent) | 3.05, 3.10 | Brightness >80% |
| Standard recycled | 2.01, 2.05 | Softness, cleanliness |
| Economy grades | 1.05, mixed | Cost |
What Are the Advantages and Disadvantages of Waste Paper?
Advantages
| Benefit | Quantification | Impact |
|---|---|---|
| Raw material cost savings | 20-50% vs virgin pulp | Direct cost reduction |
| Wood resource savings | 2.5 m³ per tonne | Forest preservation |
| Energy reduction | 40-70% less than virgin | Operating cost, emissions |
| Water savings | 50-80% reduction | Environmental, cost |
| Landfill diversion | 100% utilization | Circular economy |
| Carbon footprint | 1.5-3.0 tonnes CO₂/tonne avoided | Sustainability metrics |
Disadvantages
| Challenge | Impact | Mitigation Strategy |
|---|---|---|
| Lower tensile strength | 20-40% reduction | Virgin fiber blending |
| Lower tear strength | 10-30% reduction | Softwood virgin addition |
| Brightness limitations | Maximum 60-85% | Deinking, bleaching |
| Contamination variability | Batch-to-batch variation | Strict grading, blending |
| Stickies issues | Machine deposits, spots | Advanced cleaning systems |
| Higher fines content | Drainage, retention issues | Retention aid optimization |
| Limited recycle cycles | 5-7 times maximum | 15-25% virgin fiber makeup |
Economic Considerations
| Factor | Recycled Fiber | Virgin Fiber |
|---|---|---|
| Raw material cost | Lower (20-50% savings) | Higher |
| Processing cost | Higher (cleaning required) | Lower (simpler) |
| Product strength | Lower | Higher |
| Consistency | Variable | Consistent |
| Environmental premium | Growing market demand | Standard |
How to Test Quality for Incoming Waste Paper?
Effective quality control begins with systematic incoming material testing.
Visual Inspection Protocol
- Bale exterior examination for contamination
- Core sampling (5-10 samples per load)
- Moisture estimation
- Grade verification against specifications
Laboratory Testing Methods
| Test | Standard | Typical Values | Purpose |
|---|---|---|---|
| Moisture | TAPPI T 412 | 8-12% | Weight accuracy |
| Ash content | TAPPI T 211 | 5-25% | Filler/coating content |
| Debris content | Mill method | <1.5% | Contamination level |
| Freeness (pulped) | TAPPI T 227 | 300-600 mL CSF | Fiber quality |
| Handsheet testing | TAPPI T 220 | Variable | Strength potential |
| Dirt count | TAPPI T 437 | 5-50 ppm | Visible contaminants |
| Stickies | Mill methods | <100-500 mm²/kg | Deposit potential |
| Brightness | TAPPI T 452 | 30-85% | Deinking potential |
Key Takeaways
- EN 643 (Europe) and ISRI (North America) provide standardized classification systems enabling international waste paper trade
- Five main groups cover all recovered paper types: Ordinary, Medium, High, Kraft, and Special grades
- OCC (Grade 1.05/ISRI Grade 11) represents the largest single grade by global trading volume
- Contamination limits range from 0.25% non-paper (high grades) to 2% (ordinary grades)
- Stickies from adhesives, wax, and latex represent the most problematic contaminants for machine runnability
- Paper fibers can be effectively recycled 5-7 times before hornification limits further use
- Blending 20-40% virgin fiber with recycled stock compensates for strength losses
- Cost savings of 20-50% versus virgin pulp, with 40-70% energy reduction
- Proper grade selection based on end-product requirements optimizes both quality and economics
