New compulsory requirement from November 1

The Tenancy Lighting Assessment (TLA) is the third, and final, element of the full Building Energy Efficiency Certificate (BEEC).

Until now, only a base building NABERS Energy rating has been required under the Commercial Building Disclosure scheme.

However, from November 1 2011, the full BEEC - comprising the NABERS Energy rating, the TLA, and the Energy Efficiency Guidance - will be required on sale, lease or sublease of more than 2000sqm of office space.

A TLA of a building is based on a methodical survey of the general lighting system installed in the tenant office spaces of a building (the system that is reasonably expected to be left in a tenant space when the tenant leaves and the tenancy fit-out removed).

The TLA reports on two factors. Firstly, the overall energy efficiency of the general lighting installed (measured in watts per square metre with <7.0 W/m² considered "excellent" and >15.0 W/m2+ considered "poor").

It also reviews the installed lighting control system and categorises it as being of basic, average or sophisticated capacity; a measure of its potential to closely match the operation of the lights with the needs of the occupants.

How the TLA is conducted is covered by the newCBD Tenancy Lighting Assessment for Offices Rules( www.cbd.gov.au).

As with a NABERS rating, a TLA is valid for one year.