Back in 2012, Alpine launched a solar snow management system which has evolved into a three-component system. At the time, the system clamped directly to the panel frame in the vertical joint between the panels, and could be used on projects with Ground Snow Loads up to 50 psf (psf gsl). Today, the three-component system is recommended for all roof mounted or car port solar arrays in snowy regions with a pitch of 2/12 or greater.
This is where Alpine differs from most other snow guard manufacturers. We recognize that devices can be built to hold back an amount of weight, but that doesn’t necessarily translate to the amount of snow volume related to that weight. Physically, these brackets, when installed properly and in the right quantities, will resist snow loads up to 50 psf gsl. However, due to the need to prevent panel shading, these brackets and rails are limited to a maximum height of 2”. Our Solar SnowMax Shade Angle Analysis gives an overview of how we came to that conclusion.
Alpine does not believe or maintain that the use of 1” and 2” high rails on PV arrays will always manage the snow mass in steep-slope, high snow load regions, to the expectation of the building owner.
Our Latest Solar Snow Management Innovation
Alpine SnowGuards is constantly innovating and this is the latest three-component solar snow management system.
Within the roofing industry, there are snow guards that are 2” tall. They seem to manage the release of snow and ice adequately. Alpine has sold such systems since the late 1990’s. Solar panels do not behave like typical roofing products, though. As soon as a solar panel begins to collect sunlight and activate, it begins to produce heat. As this happens, snow and ice on the array begins to melt faster than the same snow and ice accumulated on adjacent roof surfaces.
The snow mass is managed in a way that it doesn’t suddenly evacuate the array, but it clears more quickly than the comp shingle roof itself, allowing the panels to produce electricity. Sounds great, and it is, but snow and ice will still slide from these arrays in varying amounts and at varying speeds, depending on variables such as roof pitch, snow load, vertical length of array, snow density, etc.
Managing Customer Expectations
The ideal system has the following qualities:
- Prevents a sudden release, avalanche, of snow
- Low-profile for aesthetic reasons and for the need to prevent shading
- Cost-effective and easy to install
- Will retrofit existing arrays
Our system does all of this, however, just like the comp shingle roof we talked about earlier, there will be times when snow and ice still come off. For the building owner who believes that snow guards will cure all problems, this is a less than expected outcome.
When Alpine first introduced solar snow management solutions, we intended for the PV frame-mounted snow guards to supplement the traditional roof-mounted snow guards. Alpine’s stance is that all solar snow management systems start with the installation of a roof-mounted snow management system installed below the butt of the array (with a minimum 24” landing zone). Even with the roof-mounted system, snow and ice will still come over the rails under certain conditions.
Solar Installer’s Responsibility
It’s the responsibility of the solar installer to plan new installations, while allowing for a roof landing zone and a roof-mounted snow management system to be supplemented by array-mounted devices. For existing arrays that do not have a landing zone, the installer should either remove panels to allow for the landing zone, or understand that the array-mounted snow guards alone are limited in height, and are therefore, also limited in function.
Alpine recommends homeowners reach out directly to their solar installer to start a quote via our Solar Snow Guard Calculator. Installation of our products by solar installers can protect the performance, safety and warranty of the solar array.
I hope this helps shed some light on a very important, and relatively new topic: Managing Snow on Solar.
Until next time,
Brian Stearns
President & Founder, Alpine SnowGuards
We keep snow in its place
888.766.4273
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Alpine SnowGuards designs, engineers, and manufactures snow management systems from our facility in Morrisville, VT. We work closely with leading roofing contractors, engineering firms, developers, solar installers and roofing manufacturers to ensure we deliver quality products that do what we say they’ll do. Alpine SnowGuards can help a building qualify for LEED® credits.