Frequently asked questions

Important basic info around the topics snow load, roof loads and impound water on roofs at a glance


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How to measure snow/snowload?

It is not an easy task to measure the real load of snow, since different consistencies like wet- and powder snow or even ice are varying considerably in regard to their weight. For a long time snow masses had to be cut out laboriously employing snow measuring tubes and calculating the load manually. A considerably more convenient way to do this is using an envitron snow scale, capturing and monitoring the snow load in kg/m² for 24/7 via our data portal. In case of an emergency, a snow alarm is triggered. This early warning system helps to detect potential hazard situations in due time in order to initiate a roof snow removal if necessary.

How to calculate roof loads caused by snow?

Roof loads caused by snow and ice are still underestimated. If slack water is added to the mix, roof statics are rapidly driven to their load limits. It is not an easy task to calculate snow loads properly. The load may vary considerably due to differing snow layers and by no means depends on snow depth only. So far, there were no practical methods for a simple snow load measurement. Envitron systems have now developed a monitoring system employing an automated measurement of snow loads. The snow scale captures the precise load and displays the result in our data portal, minimizing the risk of collapsing roofs. The load limits are configured individually by the customer due to building statics. Snow loads on large roof areas of schools, supermarkets, production sites, sports halls or warehouses can so be monitored conveniently. The system triggers auto-alerts on potential overload risks, so that a roof snow removal can be initiated in due time.

How to monitor the formation of snow bags?

Snow bags form on large roof areas due to roof structures, firewalls or e.g. solar modules and lead to varying roof loads. These snow load variations can only be captured by a multitude of measuring points. Envitron's newly developed extension of the snow scale, the so-called satellite-based system, may be placed in the midst of a row of photovoltaic panels and so detect pinpointedly any gliding off of snow masses from the PV fields. By employing a multitude of probing points, the true overall roof load is captured much more precisely than by one device only. This snow alert system serves as a decision-making tool for facility managers and helps reducing the risk of disasters caused by snow or collapsing roofs.

How to monitor water accumulations on roofs?

The load capacity of roof loads is limited. Due to snow and ice, but also melt water, these limits can be reached rapidly without premonition if water does not drain off properly. Envitron has now developed an impound water sensor in order to monitor flat roofs 24/7, triggering backwater auto-alert in case of overload risks. The device may also be employed for monitoring slack water on green roofs.

What is a snow management concept?

Flat roof safety is in the focus of local authorities, real estate managers, structural engineers and architects since at least the collapse of Bad Reichenhall's ice rink in 2006. However, numerous roofs collapsed due to snow load overloads in the following years. To detect and monitor the luring danger of snow masses on roofs is the first step for more safety. The solution here is envitron's snow load measuring system, which triggers alert on potential overload risks. The second step is to close and evacuate the bulding, as well as safely removing the snow from the roof, which is one of the most dangerous jobs to do. Reasons are, among others, peculiarities of structure statics, limited snow dropping points due to structural circumstances or traffics routes on roofs. Moreover, safety guidelines have to be considered. All these issues must be considered if snow removals have to be organized hastily. Therefore appropriate snow logistic concepts should be prepared in advance unhurriedly. The DGUV information paper 212-002 "snow removal on roof areas" is a model guideline published by the "Deutsche Gesetzliche Unfallversicherung". In the paper the DGUV explicitly recommend permanent monitoring of snow loads on roofs as well as surveillance by several probing points. The perfect system for this purpose is the envitron satellite-based snow load measuring system.