Sno-Safe Guide Specifications in CSI 3-Part Format
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SECTION 077523 – SNOW GUARDS
PART 1 - GENERAL
1.1 SECTION INCLUDES
A. Pad-type, flat-mounted polycarbonate snow guards.
B. Pad-type, flat-mounted metal snow guards.
1.2 RELATED REQUIREMENTS
A. Section 073113 – Metal Shingle Roofing.
B. Section 074113 – Standing Seam Metal Roof Panels.
C. Section 075000 – Membrane Roofing.
D. Section 076100 – Sheet Metal Roofing.
E. Section 086300 – Metal-Framed Skylights.
F. Section 088000 – Glazing.
G. Section 107316 – Canopies.
1.3 ACTION SUBMITTALS
A. Product Data: For each type of product, include construction details, material descriptions, dimensions of individual components and profiles, and finishes.
1. Include independent testing agency test reports for snow guard attachment shear strength.
B. Shop Drawings: Include roof plans showing layouts and attachment details of snow guards.
1. Include calculation of number and location of snow guards based upon Performance Requirements in Part 2.
C. Samples: Submit manufacturer's sample of snow guards.
1.4 INFORMATIONAL SUBMITTALS
A. Warranty Documentation: Submit sample copy of manufacturer's standard warranty.
1.5 QUALITY ASSURANCE
A. Source Limitations: Obtain snow guards from a single source from single manufacturer.
B. Manufacturer Qualifications: Company specializing in manufacturing of specified products with minimum five years' experience.
1.6 FIELD CONDITIONS
A. Weather Limitations: Proceed with adhesive-only installation when existing and forecasted weather conditions permit adhesive-mounted snow guards to be installed and adhesive cured according to adhesive manufacturer's written instructions.
1. Do not install snow guards using adhesive only when rain, snow, or excessive moisture is expected during installation or within 24 hours after installation.
2. Do not install snow guards under ambient conditions outside manufacturer's limits.
3. When conditions do not allow use of adhesive-only installation, refer to manufacturer's written instructions for mechanical fastening.
PART 2 - PRODUCTS
2.1 PERFORMANCE REQUIREMENTS
A. Shear Properties, Polycarbonate Snow Guards: Attached to metal panel mounted on plywood sheathing, per Intertek Test Report available from manufacturer:
1. Adhesive-mounted Snow Guard: Displacement, 0.113 inches at peak force of 1,220 lbf, with shear modulus of 22,300 psi, average.
2. Adhesive plus mechanical fastener-mounted Snow Guard: Displacement, 0.235 inches at peak force of 2,280 lbf, with shear modulus of 27,600 psi, average of 5 tests.
B. Shear Properties, Wide Polycarbonate Snow Guards: Attached to metal panel mounted on plywood sheathing, per Intertek Test Report available from manufacturer:
1. Adhesive-mounted Snow Guard: Displacement, 0.389 inches at peak force of 2,480 lbf, with shear modulus of 333,400 psi, average.
2. Adhesive plus mechanical fastener-mounted Snow Guard: Displacement, 0.352 inches at peak force of 2,410 lbf, with shear modulus of 30,600 psi, average of 5 tests.
2.2 MANUFACTURERS
A. Manufacturer: Sno-Safe Snow Guards, LLC, Chicopee, Massachusetts 01021. Phone (413) 592-0404. www.sno-safe.com; info@sno-safe.com.
1. Substitutions: [Not permitted] [Submit for approval by Architect in accordance with Instructions to Bidders and Division 01 General Requirements].
B. Provide snow guard installation, including attachment to roofing substrate, as applicable for attachment method, based on the following:
1. Roof snow load.
2. Snow drifting
3. Roof slope.
4. Roof type.
5. Roof dimensions.
6. Roofing substrate type and thickness.
7. Snow guard type.
8. Snow guard attachment method and strength.
9. Snow guard spacing.
10. Coefficient of Friction Between Snow and Roof Surface.
11. Factor of Safety: [2] [3].
C. Performance Requirements: Provide snow guards that withstand exposure to weather and resist thermally induced movement without failure, rattling, or fastener disengagement due to defective manufacture, fabrication, installation, or other defects in construction.
2.3 PAD-TYPE SNOW GUARDS
A. Snow Guards, Polycarbonate: [Adhered] [Adhered plus mechanically fastened] snow guards with grooved base formed for maximum adhesion, configured for multiple row installation on sloped roof as shown in approved shop drawings.
1. Product: Sno-Safe Snow Guards, LLC., Sno-Safe Original Polycarbonate Snow Guards.
2. Material: Polycarbonate with UV inhibitor.
3. Dimensions: 1.5 by 5.00 inch base by 2.32 inches tall.
4. Fastening Holes: Four, 0.265-inch diameter.
5. Color: [Bone White] [Charcoal Gray] [Clear] [Colonial Red] [Dove Gray] [Forest Green] [Mansard Brown] [Matte Black] [McDonalds Red] [Medium Bronze] [Midnight Bronze] [Musket Gray] [Slate Blue].
B. Snow Guards, Wide Base, Polycarbonate: [Adhered] [Adhered plus mechanically fastened] snow guards with grooved base formed for maximum adhesion, configured for multiple row installation on sloped roof as shown in approved shop drawings.
1. Product: Sno-Safe Snow Guards, LLC., Sno-Safe Wide Polycarbonate Snow Guards.
2. Material: Polycarbonate with UV inhibitor.
3. Dimensions: 5.25 by 3.13 inch base by 3.13 inches tall.
4. Fastening Holes: Two, 0.265-inch diameter.
5. Color: [Charcoal Gray] [Clear] [Forest Green] [Mansard Brown] [Black].
2.4 ACCESSORIES
A. Adhesive: Snow guard manufacturer's recommended adhesive applicable to roof substrate and installation conditions.
B. Mechanical Fasteners: #12 self-drilling neoprene-washer roofing screws, length as required for minimum 5/8-inch penetration into screw-holding substrate.
PART 3 - EXECUTION
3.1 EXAMINATION
A. Examine sloped roofing areas to receive snow guards. Verify surfaces to receive snow guards are secured, clean, dry, and rigid.
B. Notify Architect of conditions that would adversely affect installation or subsequent use.
C. Proceed with installation of snow guards once unacceptable conditions are corrected.
3.2 INSTALLATION
A. Install snow guards in accordance with snow guard manufacturer's and adhesive manufacturer's written instructions at locations indicated on approved shop drawings.
B. Securely attach snow guards using [adhesive] [screws and adhesive] in accordance with manufacturer's written instructions.
1. Clean each snow guard location just prior to installation.
C. Install snow guards in straight staggered rows at spacing as indicated on approved shop drawings.
3.3 ADJUSTING
A. Remove and replace damaged snow guards with new material.
3.4 CLEANING
A. Remove excess adhesive from surfaces promptly after installation.
B. Do not use harsh cleaning materials or methods that could damage surfaces or finish.
3.5 PROTECTION
A. Protect installed snow guards to ensure that, except for normal weathering, snow guards will be without damage or deterioration at time of Substantial Completion.
END OF SECTION
Sno-Safe Snow Guard layouts and quantities are estimated assuming a high of 40psf snow load based on field experience. This is the high end of snow load for the vast majority of the United States minus some specific areas. Estimating layouts and quantities for snow loads significantly above this becomes difficult if not impossible due to the fact that so many factors affect sliding snow. Any attempts at calculations in this regard should be performed by an architect familiar with the specific geographic area and specific snow conditions.
High snow load considerations:
As snow load and/or depth increases, a point is eventually reached where the holding power of the snow guard is no longer the determining factor in whether the snow can be held in place. As pressure of the snow against the snow guard increases, the shear strength of the snow itself against the face of the snow guard is what will eventually give way. Also the shear strength of the different layers of the snow, their density, and the stratification, can also become the determining factor, allowing snow to slide without the snow beneath moving.
One way to mitigate the first factor mentioned above, in unusually high snow load conditions, is to use a higher number of snow guards than typically estimated. However, with so many factors playing a role in the movement of the snow atop the roof, attempting any type of calculations or assurances, is not possible.
Another consideration is to look at using our new "Sno-Safe Wide Snow Guard". Especially if the roof is metal panel and has a 9" valley width and 2 minor ribs in the valley. This snow guard is designed to fit this type of metal roof very well. These snow guards have a larger face area which can provide greater shear resistance. Our calculator at https://sno-safe.com/spacing.html estimates both the number of Original or Wide snow guards suggested for most roofs.
Lastly, with exceptionally high snow loads, ensuring that the structure is built to withstand the weight of the snow that will be held on the roof, is especially important.
