6 June 2018
Canadan Coast Guard uses the standard developed by Technomarine
When ice drifts, the navigation lights installed on the buoys are subjected to significant mechanical stresses.
The lantern consists of a top cover, an optical system (a cylinder with a protective glass) and a lantern’s casing. The upper lid is one of the key elements of the ice lantern design as it is designed to protect the lantern from impacts of drifting ice masses.
Just as a strong wind blows off a hat from a person's head, the drifting ice can knock down the top cover from the lantern.
In order to ensure the necessary strength of the product, the manufacturer needs to know the values and characteristics of ice shocks.
Based on the data from the two-year operation of BEPA ice lanterns on the Severnaya Dvina River, Russia, and on the St. Lawrence River, Canada, and based on numerous laboratory tests, the developers of Technomarine JSC determined the values of the mechanical strength required to protect the lantern from destruction.
The obtained indicator is tentative however it allows to establish minimum requirements for the construction of products. The results of the tests were provided to the engineers of the Canadian Coast Guard upon delivery of a batch of BEPA-10LX lanterns to Canada.
In May 2018, the Government of Canada, in forming the terms for the procurement of flashlights under the Four-Season Lighted Navigation Buoys Project (4SB) (F7047-170103 / A), applied both Technomarine's tensile test method and values for static loads to be mandatory for all suppliers:
«Mechanical Strength. The lantern must be strong enough to withstand a tensile test† in which a static load is slowly increased up to a value of 80 kN. †The main housing and the upper cover of the lantern must be placed in grips and slowly pulled until a load cell in line with the pulling equipment indicates a value equal to or greater than 80 kN. It is not necessary that the complete lantern assembly be part of the test (lens or electronics can be removed)».
We hope that the newly introduced technical indicator and testing methodology will be useful for operators and manufacturers of ice-class lanterns.
Video of destructive testing of the lantern’s elements (link)