Lintel Durability - you do the maths

There are several British Standards relevant to lintel specification but none gives a difinitive guide to calculating lintel service life. - Dec 09.
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Only post-galvanising guarantees compliance with British Standards governing lintels and their durability

It is the task of the structural engineer to validate the structural performance of a lintel, including the durability features that determine lifespan. But too few recognise that only post-galvanising will guarantee modern lifespan requirements in compliance with key standards BS EN845-2:2003 and BS 7543:2003. - Dec 09.
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Arbor-Slot system meets long term conservation needs in Bradford landscaping scheme

5 April 2007

Courtesy of City of Bradford Metropolitan DCArbor-Slot recessed tree surrounds from Jones of Oswestry have met challenging spatial constraints and durability criteria at a landscaping scheme within an established conservation area in Bradford.

The units have been installed as part of landscape enhancements by the City of Bradford Metropolitan District Council to East Parade, part of major regeneration of the City’s historic Little Germany area of Victorian warehouses.

The Arbor-Slot units incorporate an innovative tree root retention and irrigation system to prevent root spread from disturbing nearby underground services while promoting healthy tree growth.

40 year lifespan

The four assemblies are also finished with Duragalv 140, a minimum 140 microns post-galvanised finish giving a minimum 40 year lifespan in relation to local atmospheric corrosivity and urban highways conditions subject to de-icing agents.

Graham Keegan of the Bradford City Team at Bradford MBC, said: “There are many listed buildings in the area so nothing is likely to change or be redeveloped. Consequently, we expect the tree units to be in the ground for a long time.

“It was demonstrated that the high specification Duragalv 140 finish would provide the long service required without maintenance or replacement.”

He added: “The tree units retain the root system and went in as one complete tailor-made unit. They could be infilled with paving to blend with the area’s character, and have slot widths designed to reduce the risk of a trip.”

Jones of Oswestry provided a total service package, encompassing site surveys, method statement and design, to manufacture, site excavation, unit installation and the laying of paviour materials. The company even sourced and planted the Pyrus Chanticlear trees required for the grids.

Measuring 1200mm by 1200mm overall, Arbor-Slot grids provide a 468mm tree aperture and incorporate 13mm wide drainage slots in compliance with BS8300 and DDA requirements.

Proven product

Peter Coe, Associate Director at the landscape architect, Taylor Young, said: “Arbor-Slot is a proven product for urban street planting. Aesthetically, it allows paving to be run right up to the tree, giving a neat, clean finish while allowing required drainage.

“Arbor-Slot meant we could avoid introducing another visual element, like an ornamental grille, to give a seamless look. With the root retention feature, it also allowed us to introduce trees where there was relatively little space for tree planting.”

Little Germany is a historic area of 19th century merchant warehouses and ornate Victorian commercial buildings currently undergoing regeneration by Bradford MDC. No fewer than 55 out of the 85 buildings within the conservation area are listed as buildings of special architectural or historic interest.

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