Interior Lighting Power Density calculation for ECBC compliance

The lighting power density or LPD is the lighting load in watts/sq ft (or watts/square meter). If the building has a plenum, it is important to know how much of this load is delivered to the space and the plenum. Lights consume electricity, and are a source of sensible load.

LPD (W/ sq. m) = Total Lighting capacity of luminaires in a space(W) / Total area of the space (sq. m)

For Interior lighting power density calculation, ECBC has two approaches which are as follows:

        <h4>Building Area Method</h4>       
    <p>Here, LPD is determined by using each appropriate building area type from Table 6-1 for ECBC Buildings, from Table 6-2 for ECBC+ Buildings and from Table 6-3 for SuperECBC Buildings.</p>       
        <h4>Space Function Method</h4>      
    <p>LPD is calculated by using each area type in a building and use allowed lighting power density from Table 6-4 for ECBC Buildings, Table 6-5 for ECBC+ Buildings and, Table 6-6 for SuperECBC Buildings.

 In cases where both a common space type and building specific space type are listed, building specific space type LPD shall apply.

1. Building Area type

(a) Calculate the gross lighted carpet area for each building area type.
(b) The interior lighting power allowance is the sum of the products of the gross lighted floor area of each building area times the allowed lighting power density for that building area type.

1. Interior Lighting Power for ECBC Buildings – Building Area Method

2. Interior Lighting Power for ECBC+ Buildings – Building Area Method

3. Interior Lighting Power for SuperECBC Buildings – Building Area Method

1. Building Area type

(a) Determine the appropriate building type and the allowed lighting power density from Table 6-4 for ECBC Buildings, Table 6-5 for ECBC+ Buildings and, Table 6-6 for SuperECBC Buildings. In cases where both a common space type and building specific space type are listed, building specific space type LPD shall apply.
(b) For each space, enclosed by partitions 80% or greater than ceiling height, determine the gross carpet area by measuring to the face of the partition wall. Include the area of balconies or other projections. Retail spaces do not have to comply with the 80% partition height requirements.
(c) The interior lighting power allowance is the sum of the lighting power allowances for all spaces. The lighting power allowance for a space is the product of the gross lighted carpet area of the space times the allowed lighting power density for that space.

Interior Lighting Power for ECBC Buildings – Space Function Method, LPD for ECBC+ and Super ECBC can be accessed in ECBC 2017 in tables 6-5 & 6-6.