UNDERSTANDING AND USING: AAMA 450 VOLUNTARY PERFORMANCE RATING FOR MULLED FENESTRATION ASSEMBLIES

Joseph Reed, PE - Senior DirectorMarch 1, 2018

In the beginning …CAN/CSA A440-00 a CSA standard used in Canada.

Code reference with vague certification and labelling requirements.

101/I.S.2/NAFS-02 an AAMA/WDMA standard used in USA.

Explicit Code requirement for certification and labelling.

In 2005 the harmonized standard AAMA/WDMA/CSA 101/I.S.2/A440-05 was introduced.

Currently AAMA/WDMA/CSA 101/I.S.2/A440-17.

NAFS PRIMER

AAMA 101, the basics (pun intended)

Standard provides basic requirements for testing fenestration products for the purposes of certification.

Groups products by PRODUCT TYPE and provides sub-divisions for PERFORMANCE CLASS.

For a particular PRODUCT TYPE and PERFORMANCE CLASS standard size windows (GATEWAY) are tested to a minimum PERFORMANCE GRADE.

Depending on PRODUCT TYPE, supplemental tests are performed.

NAFS PRIMER

Beyond the Gateway …Standard allows for downsize test units of similar construction to achieve higher PERFORMANCE GRADE. Full test program typically not required. Testing may be done long after gateway test. Great option for meeting a particular project specification.

Standard allows for Alternative Minimum Test Size (i.e. alternate gateway) for R Performance Class.

Other program documents add flexibility to standard. For example, AAMA 103 Procedural Guide for Certification of Window, Door and Skylight Assemblies allows for Waiver of Retest.

Mulled Assemblies addressed by AAMA 450 Voluntary Performance Rating Method for Mulled Fenestration Assemblies.

NAFS PRIMER

OBJECTIVES

Review Code requirements for mullions and tie-in with AAMA 450

Step-by-Step examination of AAMA 450

Discus the best approach for using AAMA 450

Provide some examples

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IS AAMA 450 A CODE REQUIREMENT? Full disclosure - I am not an expert on

the Canadian codes or regulations.

2015 National Building Code of Canada referencesANSI/AAMA/CSA 101/I.S.2/A440-11

ANSI/AAMA/CSA 101/I.S.2/A440-11 has mullion requirements and ties you to AAMA 450

US Codes are a little more explicit.

2015 NBC 5.9.2.21) Windows, doors and skylights shall conform to the requirements ina) AAMA/WDMA/CSA 101/l.S.2/A440, andb) CSA A440Sl, Canadian Supplement

A440-11 4.6.1 Mullion ratings shall be determined according to the requirements and procedures of AAMA 450 (i.e.,air, water, and structural) and the ratings shall become a part of the test record for the composite units ormulled combination assembly.

US Building Code Requirements for Mullions

2006 IRC2009 IRC2012 IRC2015 IRC2018 IRC2017 FBC

Insulating glass units and how they fail testing

Code

2006 IBC

(Texas TDI) 2009 IBC 2017 FBC

2012 IBC

2015 IBC

2018 IBC

AAMA 450-00 AMMA 450-06 AMMA 450-10 AAMA 450-10

From -00 to -06: Added 7.3 for air/water sizes different from structuralAdded clarification about L/175 based on product classAdded Note 2 about sealing units during water test.Added 8.3.1 that structural load proves anchorageAdded 9.0 Submittal PackageAdded Appendix 2: Engineering Design Rules

From -06 to -10 Re-formatted and updated reference standards.

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IT IS IN THE CODE, SO WHAT? Certification and labeling requirements

are vague and confusing.

Except for egress, windows are not thought of in terms of Life/Safety

Focus is primarily on energy issues.

Think of AAMA 450 as a method to be exploited rather than a cumbersome regulation.

Scope

Procedures and requirements for determining the air infiltration, water resistance and structural performance of factory built or knocked down and field mulled fenestration assemblies.

Presents test procedures and calculation procedures for structural performance.

Provides a means of Grouping mulled fenestration assemblies.

Windows making up the assembly have already been evaluated with A440.

AAMA 450 RATING OPTIONS

Option 1 - Test Total Assembly(+) Covers mandatory air/water testing(+) exempt from L/175 deflection limit for R and LC(+) PE review and seal not required(+) Follow on calculations for alternate sizes (8.1)(-) Test specimen prep, test specimen cost and test lab scheduling

PART I – MULLION EVALUATION

Option 2 - Test Mullion Element

(+) Minimal test specimen prep and test specimen cost(+) More favorable results than Option 3(-) Analysis by PE(-) L/175 limit deflection limit applies for all grades(-) Follow on air/water test required(-) Anchor analysis

PART I – MULLION EVALUATION

Option 3- Engineering

(+) No test specimen(+) Quick, inexpensive evaluation of many profiles.(-) L/175 deflection limit applies for all grades(-) Follow on air/water test required(-) Anchor analysis(-) No credit for partial composite action or PVC

PART I – MULLION EVALUATION

Part I – Mullion EvaluationDiscussion:

§ Option 1 seems the most logical as follow on air/water testing is required for others.

§ Option 1 should not be undertaken without thorough planning and anticipation of Grouping

§ Option 2 is best suited for composite mullion elements that would be conservatively analyzed by Option 3

§ Option 3 is a valuable component of Grouping

§ Option 3 is valuable for existing testing where optional water tests have been performed.

Part II - Grouping

§ Qualifying multiple combinations with a limited test plan

§ By comparing section properties stiffer and stronger combinations can be proven by the testing of a less stiff and weaker combination

§ The stiffer and stronger combinations can only claim the performance of the less stiff and weaker test specimen

§ Comparisons are done by PE

§ Very similar to analyses for AAMA 103 Waiver of Retest

Part II - Grouping

§ Comparisons can be done prior to testing to establish the most advantageous test plan.

§ Comparisons may be used to suggest several test specimens over several product grades (good, better, best).

§ Comparisons can be done well after the testing as new products are proposed and developed.

§ Stress and deflection analyses, if performed for grouping may reveal to more advantageous design pressures.

Example AAMA 450 Option 2 – Test Mullion Element

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0.000 0.200 0.400 0.600 0.800 1.000

Appl

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Load

(lb)

Deflection (inch)

Actual Residiual Actual Residual Actual Residual20 -0.13 0.02 1.56 0.69 -0.07 0.0230 -0.17 0.02 2.79 0.59 -0.12 0.0240 -0.23 0.03 3.98 0.5 -0.18 0.0250 -0.28 0.03 5.24 0.17 -0.23 0.0260 -0.32 0.04 6.64 0.16 -0.28 0.0470 -0.36 0.05 7.92 0.13 -0.33 0.0480 -0.41 0.05 9.22 0.14 -0.39 0.0490 -0.44 0.06 10.65 0.13 -0.45 0.04100 -0.47 0.08 11.89 0.14 -0.5 0.03120 -0.52 0.07 14.62 0.14 -0.6 0.03130 -0.57 0.08 15.99 0.15 -0.67 0.04150 -0.65 0.09 18.73 0.06 -0.81 0.04180 -0.76 0.1 22.68 0.06 -0.99 0.04195 -0.8 0.11 24.65 0.1 -1.11 0.04

Deflection (mm)Load (lbs) Gauge 1 Gauge 2 Gauge 3

L/175

1.5x120

lb

Example AAMA 450 Grouping

CONCLUSIONAAMA 450 is a very flexible standard providing multiple options for rating mulled fenestration assemblies.

The requirement that all options have a air/water test and the relief of the L/175 deflection requirement for Option 1 –Assembly Test make Option 1 a logical choice.

Grouping is a powerful mechanism for developing test plans and qualifying many product types under one program. Grouping should always be the first step.

DETAILED EXAMPLES FORAAMA 450 VOLUNTARY PERFORMANCE RATING FOR MULLED FENESTRATION ASSEMBLIES

Joseph Reed, PE - Senior DirectorMarch 1, 2018

OBJECTIVES

AAMA 450 Option 3 – Structural Calculations by PE for Composite Mullion Elements

AAMA 450 Option 2 –Mullion Element Test with Engineering Analysis

AAMA 450 Option 1 Test Total Assembly with AAMA 450 Grouping Analysis

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Option 3- Engineering

(+) No test specimen(+) Quick, inexpensive evaluation of many profiles.(-) L/175 deflection limit applies(-) Follow on air/water test required(-) Anchor analysis(-) No credit for partial composite action or PVC

COMPOSITE MULLION EVALUATION

Objective: Determine the load carrying capacity of a mullion constructed of wood window components, aluminum cladding and steel reinforcing. The analysis shall consider the allowable bending stress in every element and the overall deflection of the mullion.

Transform all sections to wood; IiW (subscript W means Wood) (IiW = Ii(Ei/EW) )

Calculate total transformed moment of inertia, Itot = Σ Ii(Ei/EW) Distribute moment according to Mi = Mtot(IiW/Itot) = Mtot(IiEi/EW)/Itot

Determine allowable load on each member according to the member's allowable bending stress

Check overall deflection of transformed section; if greater than L/175 scale design pressure such that deflection equals L/175.

Option 2 - Test Mullion Element

(+) Minimal test specimen prep and test specimen cost(+) More favorable results than Option 3(-) Analysis by PE(-) L/175 limit deflection limit applies(-) Follow on air/water test required(-) Anchor analysis

MULLION ELEMENT TEST AND EVALUATION

Regimented Test Procedure to Cover Three Evaluation Criteria

1. L/175 Deflection Limit2. L/250 Permanent Set Limit3. Factor of Safety of 1.5

Apply load and unload incrementally checking each load for L/175 Deflection Limit and L/250 Permanent Set.

If L/175 limit is achieved, must incrementally load until Factor of Safety of 1.5, mullion failure or L/250 Permanent Set is achieved.

Back-calculate mullion load capacity.

MULLION ELEMENT TEST AND EVALUATION

MULLION ELEMENT TEST

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0.000 0.200 0.400 0.600 0.800 1.000

Appl

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Load

(lb)

Deflection (inch)

Actual Residiual Actual Residual Actual Residual20 -0.13 0.02 1.56 0.69 -0.07 0.0230 -0.17 0.02 2.79 0.59 -0.12 0.0240 -0.23 0.03 3.98 0.5 -0.18 0.0250 -0.28 0.03 5.24 0.17 -0.23 0.0260 -0.32 0.04 6.64 0.16 -0.28 0.0470 -0.36 0.05 7.92 0.13 -0.33 0.0480 -0.41 0.05 9.22 0.14 -0.39 0.0490 -0.44 0.06 10.65 0.13 -0.45 0.04100 -0.47 0.08 11.89 0.14 -0.5 0.03120 -0.52 0.07 14.62 0.14 -0.6 0.03130 -0.57 0.08 15.99 0.15 -0.67 0.04150 -0.65 0.09 18.73 0.06 -0.81 0.04180 -0.76 0.1 22.68 0.06 -0.99 0.04195 -0.8 0.11 24.65 0.1 -1.11 0.04

Deflection (mm)Load (lbs) Gauge 1 Gauge 2 Gauge 3

L/175 Limit Achieved

1.5x120lb; perm set OK, no failure

GROUPING OF MULTIPLE DESIGNS FOR QUALIFICATION BY A SINGLE EVALUATION6.1 Grouping of mulled fenestration assemblies is allowed for the purpose of qualifying multiple designs with a single evaluation. As a minimum requirement, the following items must be considered when grouping assemblies. Additional considerations may be required for specific product groupings.

6.1.1 Material and Section Properties: Moment of Inertia, Section Modulus, Modulus of Elasticity, Yield Stress and Maximum Fiber Stress.

6.1.2 Load Distribution: Configurations, window type(s) and attachment.

6.1.3 Method of mullion attachment to rough opening or window frame.

6.1.4 Sealant details for air leakage and water resistance groupings.

GROUPING OF MULTIPLE DESIGNS FOR QUALIFICATION BY A SINGLE EVALUATION6.2 Grouping for the purposes of air and water performance may be different than the grouping for structural performance.

6.3 A licensed Professional Engineer (P.E.) shall review all mulled fenestration assemblies within the manufacturer’s specified grouping in order to determine the weakest and/or minimal performing product. A letter, signed and sealed by the licensed P.E., shall be provided to the evaluation or test agency. Attached to the letter shall be detailed drawings of the referenced individual mulled fenestration assemblies.

6.1.1 Materials and Section Properties

6.1.2 Load Distributions Generic mullion analyses are used to investigate the effect of load distribution on the mullion response.

Using the load distribution effects, the stiffness and strength of the components are normalized with respect to the casement/casement combination.

Proposed Test Specimen

Test for highest possible water performance. This value may be used to support future Option 3 evaluations.

It is permissible to seal the individual units in order to determine the maximum water penetration resistance of the mullion.

Deflection under load is not part of the pass/fail criteria but should be recorded to assist future Option 3 evaluations.

RECOMENDATIONS