SOLAR PANELS, TYPHOONS, AND CLAMPING ZONES
IMPORTANCE OF CLAMPING ZONES
Clamping zones are areas along the rim of a solar panel where they have to be clamped down either to a roof-rack railing or a ground mount structure.
Clamping zones vary from panel to panel in size and position and are identified in the Solar Panel installation manual.
Clamping zones are sometimes ignored by installers of solar panels, yet they play an important role in your warranty claim (if ever) and the wind force a panel might be able to cope with during a typhoon.
If you have no access to the installation manual, it is safe to assume that the clamping zone is in the same location as the perforated mounting hole in the frame. They normally have a length of about 30 cm, so 15cm on each side of the hole is a safe bet when no installation manual is provided.
Because the Philippines is a country exposed to typhoons, clamping zones play a more important role than in a lot of other countries. It is only common sense that you want to have your panel mountings optimized to withstand high wind forces without any compromise.
But… Let’s start at the beginning. In most cases, a roof mounting system may consist of the following:
1. Rails (to provide a platform for mounting the modules)
2. Splices (to connect rails as needed)
3. Mid clamps (to be located between each module)
4. End clamps (to secure the end of the last module)
5. L-feet or standoff (to secure the rail to the roof)
Clenched (mid and end) clamps are the usual method to mount panels onto a rooftop or a base structure.
Solar panels are often mounted without consulting their installation manual, and that is wrong. The panels, like other solar components, are subject to warranties, and these warranties might become void if the grounding and clamping instructions are not followed.
SOLAR MOUNTING AND TYPHOONS!
Normally, clamps are guaranteed for 5400 Pa in their most optimal configuration. This typically matches a 100 km/h wind speed. A typhoon’s speed ranges between 115 and 180 km/hr.
To put things in perspective, typhoon Yolanda (remember that one?) had gust winds of 315 km/h!
It needs no further explanation. The panels in this picture stand no chance in a typhoon!
Also bear in mind that the maximum surface load capacity of a panel is often rated at 5400 Pa.
In our research, the clamping of panels should be a minimum of 4 pieces in the position of the recommenced clamping zones to be compliant with this 5400Pa target.
In the below picture, there is an indication of how the mountings are compromised to withstand wind force in various clamping scenarios:
Typically, in the Philippines, the rafter (C-purlins) has an intermediate distance of 60cm. This more than often limits the installer’s ability to put the clamps in their optimal recommended location and sometimes (unknowingly) compromises the Pa resistance of the mounting systems. Especially with the common trend of bigger and bigger panels, it is good practice to mount your panels with 6 clamps (3 on each side) for added resistance against typhoons.
Shown is a picture of an installation of Solana4U in Iloilo, which as a standard practice, supports its panels with 6 clamps and UV-resistant flexible conduit pipe.
It is good to check with your installer to see if he is able to mount the panels in accordance with the installation manual. If not, he should add railing support and clamps to compensate for that. GET FREE ASSESSMENT NOW!
Keywords: wind resistance, clamping zones, installation manual, solar roof mounting system
