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US Voluntary Product Standard PS 2-10  – the Performance Standard for Wood-Based Structural Panels

PS2-10 Performance Standard for Wood-Based Structural-Use PanelsPS 2-10 is a performance-based standard which defines the end use application of a wood-based panel, such as plywood, OSB or composite panels. It defines the requirements for the use of wood-based panels as structural components which are recognised throughout North America.

PS 2-10_APA Guide with Typical APA Trademarks

The APA edition of the updated structural-standard with typical APA trademarks provides information on performance requirements, adhesive bond performance, panel construction and workmanship, dimensions and tolerances, marking, and moisture content of structural-use panels. Revised June 2011.

The standard establishes structural criteria for assessing the acceptability of plywood, OSB and composite panels for load bearing sheathing applications in construction such as floors, walls and roofs.  It covers performance requirements, adhesive bond requirements, panel construction and workmanship, dimensions and tolerances, marking and moisture content.  It also includes test methods to determine compliance.

Official definitions

  • Plywood – a conventional all veneer panel with alternate layers of veneer running perpendicular to one another.  For veneer panels, a layer is a single veneer ply, or two or more adjacent plies, with the grain direction parallel
  • OSB: oriented strand board is a type of mat-formed panel with oriented layers resulting in directional properties
  • Composite – referring to any panel containing a combination of veneer and other wood-based material
  • Mat-formed panel – any wood-based panel which does not contain veneer, consistent with the definition of structural-use panels.

 Requirements

The standard defines the terms associated with wood structural panel manufacturing to provide a common language across the industry.   All the panels conforming to this standard must meet or exceed the following requirements:

General requirements: Dimensional tolerances and squareness of the panels, including their performance category and thickness tolerance.  The veneer used must be in accordance with the veneer grades and workmanship given in PS 1-09 for plywood.

 Performance requirements: Panels have to pass performance criteria covering three areas  – structural performance, physical properties and adhesive bond performance.

  •  Structural performance deals with concentrated and uniform loads, wall racking and fastener holding.
  • Physical properties cover dimensional stability, bond performance.  Plywood can have a bond classification of either Exterior or Exposure 1, while OSB, composite and mat-formed panels can only have an Exposure 1 classification.

Moisture content: Panels must have a moisture content of less than 16% at the time of shipment and at the time of testing.

 Qualification Testing and Mill Specification: Providing test specimen requirements, conformance criteria, and mill specifications.

Qualification Testing: These tests cover structural, physical product properties and adhesive performance within the above ‘Performance Requirements’.  Each has its own series of tests for:

Structural use:

  • Uniform load
  • Concentrated load (static & impact)
  • Nail holding
  • Racking shear

Product properties:

  • Dimensional stability
  • Bond performance

Mill Specification: A propriety mill specification is written. once a panel type has passed the qualification testing process, This mill specification is unique to the particular panel type and for that specific mill and must be used for on-going quality assurance procedures. This specification covers:

Mechanical properties:

  • Large panel bending stiffness and strength tests
  • Small specimen bending stiffness and strength tests

Physical properties:

  • Panel grade
  • Panel thickness – see Appendix D
  • Moisture content
  • Linear expansion

Adhesive bond properties:

  • Plywood
  • OSB
  • Composite and mat-formed panels

Test Methods:  An outline of the exact test methodology to be followed to determine compliance with the standard.  It gives the equipment, specimen preparation and procedure for each specific test as follows:

  • Concentrated static and impact load
  • Uniform load
  • Wall racking load
  • Fastener holding resistance
  • Large panel bending
  • Small static bending for OSB and composite and mat-formed panels
  • Linear expansion measured from oven dry or 50% relative humidity to vacuum pressure soak
  • Linear expansion and thickness swell measured after wetting one side
  • Linear and thickness expansion measured by exposure to relative humidity
  • Determination of panel moisture content
  • Determination of panel thickness
  • Probe test for delamination
  • Adhesive mould test
  • Adhesive bacteria test
  • Moisture cycle test for bond performance
  • Moisture cycle test for delamination and strength retention
  • Bond performance for plywood with knots and knot holes
  • Radial probe test
  • Dead weight stiffness (EI)

Trademarking and Certification: Panels conforming to PS 2-10 are obliged to carry the stamp of a qualified inspection and testing agency.  This also includes the panel’s grade name in line with its end use application as well as the manufactured nominal thickness; its ‘Performance Category’; span rating; bond classification and the symbol PS 2-10.

For mat-formed panels with orientated strands, these must also carry marks indicating the panel’s strength axis.

APA is the voluntary product standard sponsor and organized the PS 2 Standing Committee that developed the revisions.

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All Questions OSBPlywood

What are the main changes to the FSC Chain of Custody Certification standard?

Download What’s New in FSC revised COC standard.   Also, the previous FSC compulsory verification programme has been replaced by a due diligence protocol with a new risk assessment system. Learn more.  North American good forestation practice supports the aims of EUTR.  Its sustainably managed forests comply with one or more of the five leading certification agencies responsible for verifying proper forestry practices.

 

Can US Underwriters Laboratories certified EPDs be used for environmental performance ratings under the BREEAM system?

Learn how APA products can count towards a building’s BREEAM rating.  The British Research Establishment and the US Underwriters Laboratories  now recognize each other’s certified EPD making it simpler for APA member mills to gain environmental performance ratings under the BRE Environmental Assessment Method  (BREEAM).

Does APA plywood meet the lowest category (E1) for formaldehyde release without need for further testing?

Under the harmonised European Standard for wood-based panels, EN 13986, Annex B, ‘wood-based panels glued with resins emitting either no formaldehyde or negligible amounts of formaldehyde after production as e.g. isocyanate or phenolic glue’ are to be classified as E1 (the lowest formaldehyde release class) without further testing.

See APA’s guide Formaldehyde and Engineered Wood Products.  APA plywood is designated under the lowest E1 category for formaldehyde release without needing further testing.  APA’s US PS 1 and PS 2 plywood have been tested to EN 717-1 and formaldehyde levels already meet the requirements for the E1 classification limit.

Also see:  Formaldehyde (plywood) and Formaldehyde (OSB).

 

 

Can APA plywood and OSB be used in non-construction applications?

US plywood and OSB are equally effective as sturdy, robust and cost-effective solutions  for non-construction applications – from shelving, site hoardings , protective linings in the cargo bay of delivery vehicles to packaging and furniture.   See APA’s Performance Panels.   Need help to decide what grade or type of panel to use for a specific application? APA’s Industrial Panel Selection Guide (Form T200) is another easy to use resource.

How do I equate product Use Classes with the Service Classes given in Eurocode 5 for the design of buildings using engineered wood products?

See APA’ s guide  to Service Classes and Use Classes. For maximum biological durability, both Service Classes and Use Classes must be considered when specifying US CE-marked panels .  This guide helps you make the right selection.

 

‘Hazard classes’ have been replaced (see updated EN 335:2013) by Use Classes covering plywood and OSB.  They will also cover LVL when the LVL standards have completed their current update.  Use Classes are based on different environmental exposures that can make the panel susceptible to deterioration. , as given in Eurocode 5, are used for assigning  strength values and calculating deformation in load bearing situations.  They are determined by the moisture content of the panel corresponding to the environmental humidity and temperature during service.

How do APA’s member’s products count towards a sustainability assessment for new construction or in refurbishment projects?

The British Research Establishment and the US Underwriters Laboratories  now recognize each other’s certified EPD making it simpler for APA member mills to gain environmental performance ratings under the BRE Environmental Assessment Method  (BREEAM).  This is the UK’s leading and most widely used environmental assessment method for buildings and communities. It sets the standard for best practice in sustainable design and has become the de facto measure used to describe a building’s environmental performance. Learn how APA products can count towards a building’s BREEAM rating.

What is a ‘life cycle stage’ and how do these link to the environmental assessment of whole buildings?

A good starting point is our Green Topics section and  Types of EPD and the five life cycle stages

How do core category rules link with environmental product declarations?

EN 15804:2012 +A1:2013 provides the core Product Category Rules (PCR) for the production of Environmental Product Declarations (EPD) for all construction products and services.  Review with main environmental standards.  For more details see: Core Product Category Rules (PCR) for Products and Services. 

Whose responsibility is it to check that wood products being imported into the EU do not originate from illegally sourced timber supplies?

The European Union Timber Regulation (EUTR) puts specific obligations on operators and traders . Operators (or importers) are any (natural or legal) person first placing timber on the EU market. They must maintain records of any traders that they supply timber to.  They must implement a due diligence system to minimise the risk of putting illegal timber or any of its derived products on the market.  Learn more.

Does the EUTR require mills to provide any extra documentation for customs entry into the European Union?

The European Union Timber Regulation (EUTR) puts specific obligations on operators and traders and applies to timber originating in the domestic (EU) market, as well as from third (non-EU) countries such as North America. The information it requires has to be retained for at least five years and be available on request.  See European Timber Regulation.

Must all plywood and OSB panels carry a CE marking?

Manufacturers of wood-based products  covered by either a harmonised European standard (hEN) or a European Technical Assessment (ETA) must apply for CE marking under the 2013 Construction Products Regulation.  See CPR & CE Marking  and our Official Guidelines section.

What is the definition of a construction product under the CPR?

This applies to any product or kit which is produced and placed on the market for incorporation in a permanent manner in construction works or parts thereof and the performance of which has an effect on the performance of the construction works with respect to the basic requirements for construction works.’

Products must clearly display the CE mark and have the correct Declaration of Performance documentation.  For more info: CPR & CE Marking.

What is a Declaration of Performance referred to under the Construction Products Regulation?

Under the CPR, manufacturers wishing to trade in the European market are legally required to set down the levels of performance for any construction product.  They have to be listed in an official document called a Declaration of Performance.

What is the difference between Structural 1 and Exposure 1?

Exposure 1 is a glue bond classification.  It uses the same 100% waterproof glue as exterior panels and refers to a panel’s durability when long delays in construction are expected or when facing high moisture content. For plywood, see  https://apawood-europe.org/products-trademarks/plywood/trademarks/glue-bond/.  For OSB:  https://apawood-europe.org/products-trademarks/osb/trademarks/exposure-durability-classification/

Structural 1 refers to a panel’s superior performance characteristics.  For OSB, see https://apawood-europe.org/products-trademarks/osb/comparable-performance-requirements/

For Structural 1 plywood,  all panels have special improved veneer grades and if manufactured to the American PS1 standard, the veneer grades will be species with a Group 1 strength classification.  See group classification of species.

 

The CE-mark on an APA plywood panel means it conforms to European Standards – but which ones?

Plywood Design Information looks at the plywood grades A-A, A-B, A-C; B-B, B-C; C-C, C-D and the relevant standards that the trademarked panels comply with.

 

I want to use a Rated Sheathing panel for flooring/ roofing application, what info do I need to know?

For plywood, see Span rating.  For OSB, see Span rating. A full range of technical information in under Products and Trademarks.

What extra strength benefits do Structural 1 OSB panels provide over standard Rated Sheathing panels?

OSB Structural I  on an APA trademark indicates that the OSB structural-panel meets the requirements of a Performance Rated panel.  This delivers superior design capacity for these panels over OSB Rated Sheathing and Sturd-I-Floor.  Also see Comparison of Superior Design Capacities for OSB Structural I Sheathing with OSB Rated Sheathing.

What is the difference between a touch-sanded panel and sanded panel?

Veneer in a finished US trademarked plywood panel must conform to one of the six grades listed in the US PS 1-09 standard: N, the highest classification (rarely produced), followed by A, B, C-plugged, C and D.  Non-overlaid APA plywood panels come in three levels of surface finish – sanded, touch-sanded and unsanded.

Also see veneer grades for Popular APA Plywood Panels.

How do APA veneer grades match those given in the European standards

APA has produced two easy to follow guides to help match the grade numbers given on a US finished plywood panel with the requirements of  EN 635-3.

Detailed guide listing permissible defects – with maximum sizes.

Simplified guide to the US PS 1-09 veneer grading rules and appearance grades in EN 635-3 based on the appearance of the surface veneers. Equivalents cannot be exactly compared as two different sets of grading rules apply.

How do I correctly gauge the face appearance a plywood Siding panel?

I want to specify an APA panel for concrete formwork – what do I need to know?

See APA’s comprehensive Concrete Forming Design/Construction Guide for architects, engineers and contractors and the types of APA concrete forming plywood panels.

Are APA panels tongue and grooved on all four edges?

APA panels have a tongue and groove profile on their two long edges.  This eliminates the need for support (blocking) under adjacent panel edges to prevent them from deflecting independently of each other when load is applied.  See Tongue & Groove  (plywood) and Tongue & Groove (OSB).

I am not familiar with the term ‘Sized for Spacing’ – what is its significance?

‘Sized for Spacing’ on APA Rated Sheathing, APA Rated Sturd-I-Floor and APA Rated Siding trademarks indicates that the manufacturer has produced the panel to a size slightly less than the traditional nominal 2440mm (96″) by 1220mm (48″).  It is done to facilitate proper panel spacing during construction.  See Sized for Spacing  (plywood) and Sized for Spacing  (OSB).  For further technical details see Product and Trademarks.

How are Performance Category and thickness related?

Performance Category, Panel Thickness and Span Ratings are key categories that need to be considered together.  See Thickness, Performance Category  (plywood) and Thickness, Performance Category (OSB).

I’d like to know more about a panel’s Span Rating and how it links to thickness.

Plywood: Span rating
OSB: Span rating

What is Span Rating on the APA trademark and why is it important?

Span Rating denotes the maximum recommended centre to centre spacing of supports in inches over which the panel should be placed with its strength axis across two or more supports. Plywood: Span rating.  OSB: Span rating

What is the difference between Exposure 1 and Exterior plywood panels? What are their appropriate uses?

Bond classification relates to moisture resistance of the glue bond and therefore to the structural integrity of the panel.  See glue bond durability classification (plywood) and exposure durability (OSB).

What are the main OSB panels likely to be available in Europe?

See APA’s guide to panel grades  and also info on understanding the trademark.

What are the main plywood panels likely to be available in Europe?

What are the main European standards that I would need to be aware of for OSB panels?

The main standards are: EN 13986 and EN 300.   But also see the other relevant standards for OSB.

What are the main European standards that I would need to be aware of for plywood panels?

The main standards are: EN 13986, EN 636, EN 314, EN 635-3.  And for more details, see EU standards for plywood.