Family Grouping Testing Requirements

Family Grouping Testing Requirements

The Family Grouping policy is designed to reduce testing burden as well as reduce the total application fees required by manufacturers to list groups of products that comply with the Family Grouping definition, relative to testing and listing all products individually. By identifying the worst case models within a family group, limited testing can be provided if the worst case models demonstrate compliance with the Technical Requirements. As many of the Technical Requirements are minimum requirements, by demonstrating that the worst case models within a group meet the minimum requirements, it can be assumed that models performing better than the worst case models will also meet the requirements, and therefore do not require testing. The following testing requirements include the minimum testing required for a family group.

Required Testing

Click on any of the criterion below to read about additional testing guidance.

Independent Test Reports Required for Each Group
Criterion Test Required
Minimum Light Output LM-79
Allowable CCT LM-79
Minimum CRI LM-79

Power Quality

(THDi and Power Factor)



Independent Test Reports Required for Each Family Group or Sub-Group of a Family Group
Criterion Test Required
Minimum Efficacy LM-79
Minimum L70 Lumen Maintenance


LM-80 for single LED package/module/array as required for Lumen Maintenance projection through Option 1

Driver Reliability

(applicable to products seeking DLC Premium Classification only)

Driver ISTMT


In House Test Reports Allowed: Test Reports Required for Each Group
Criterion Test Required
Zonal Lumen Density LM-79
Driver Characteristics

Driver output electrical measurements


Testing Guidance


Minimum Light Output
  • The product that is expected to have the lowest overall light output (or lumens-per-foot, as applicable) must be tested according to LM-79. In general, this is expected to be the product with the fewest number of LEDs, lowest drive current, least efficient optic, and lowest CCT within the family group.
  • Please note that if your family group application seeks qualification for your products in more than one Primary Use designation, testing must demonstrate compliance with the requirements for each Primary Use. This may result in the need to provide additional worst case light output LM-79 test reports, or for a single test to be evaluated more than one time.
  • The only exception to the above will be for groups that cross light output bins in outdoor categories: while these groups must supply worst case light output testing for the whole group, determination of the appropriate bin for family members will be made on the basis of the scaled performance table. Please note that testing must still demonstrate compliance with all efficacy levels, as noted below in the efficacy testing section.
Allowable CCT
  • Testing must be provided on a product that is at the representative highest CCT within the family group. For example, if the group includes products at 3000, 4000, and 5000K, at least one product at 5000K must be tested.
  • Please note, because DLC requirements have lower- and upper-bounds on CCT, color data will be needed at both the lowest and highest CCTs. However, since the worst-case efficacy and worst-case light output products are expected to be at the representative lowest CCT, it is expected that tests for those parameters will cover this need.
  • The LM-79 test report provided to satisfy this requirement must at least contain section 12 color measurements for a representative model at the highest CCT within the family group.
Minimum CRI
  • Testing must be provided on the product that is expected to have lowest representative CRI within the family group. For example, the group includes 80 CRI and 90 CRI variations, testing must be conducted on at least one 80 CRI variant.
  • The LM-79 test report provided must at least contain section 12 color measurements for the model that represents the lowest CRI option.
  • Note that CRI variations are expected to affect light output, efficacy, and thermals. CRI variations should be considered when determining overall worst case light output, efficacy, and thermal models within the family group.
Power Quality
  • Electrical testing must be provided for the product that is expected to have the worst-case THD and PF in the group. In general, this is expected to be on the product with the driver with the least optimal loading condition. In situations where there is more than one driver in the group, in-house testing will be needed to demonstrate that the worst-case driver, loading condition, and input voltage have been selected for testing.
  • Power factor and THD graphs that compare the loading of the driver to the power quality performance must be provided for each driver of the family group, along with bench-top testing on the worst case loading for each driver used.
  • In-house testing is allowed for power quality metrics.
Minimum Efficacy
  • Testing must be provided for each product expected to have the lowest lumens per watt in each sub-group of the family. When determining worst case efficacy, manufacturers must demonstrate that they are factoring in all variations that will affect this metric, including light output (LED counts and drive current), CCT, optical efficiencies, driver and applicable operating conditions, and thermal effects.
  • Note that there are many factors that can influence efficacy. Manufacturers shall determine and justify the combination of factors that result in the worst case efficacy of each sub-group. DLC always reserves the right to ask for additional information to clarify or verify technical justification.
  • If the family contains multiple drivers, driver spec sheets with efficiency curves must be provided, as well as bench-top testing demonstrating the driver efficiency at the applicable loading conditions and at the applicable input voltages.
  • Please note that if your family grouping crosses requirement variables that have different efficacy requirements - for example, across classifications or across light output bins for outdoor products, when there are both Premium and Standard classification products within a family, or when products eligible for allowances and products not eligible for allowances are included in the same family  - testing must demonstrate that the products in the group meet all applicable requirements. This may result in the need to provide additional "worst case efficacy" LM-79s.
Minimum L70 Determination
  • The product with the worst case lumen maintenance must demonstrate that it meets the DLC lumen maintenance requirements. Critically, this is normally expected to be on the product where the LED is operating at its highest temperature within the group. An ISTMT to support TM-21 projections must be conducted on the hottest LED in this (hottest) luminaire.
  • This product is typically the model with the greatest number of LEDs, operated at the highest drive current, using the least efficient optics, and having the lowest CCT that results in the shortest life referenced as L70. If applying under Premium, the worst case thermal management model must also meet the L90 requirement.
  • Worst case thermal measurements are required for each sub-group, as applicable.
Driver Reliability
  • If the manufacturer is applying for the DLC Premium designation, the family group must demonstrate that the driver(s) used in the family meet the driver reliability requirements. This means an ISTMT of the driver(s) must be conducted on the worst case product within the group or sub-group, as applicable, and must be supplied along with the appropriate driver spec sheets showing TMP location and reliability under allowable operating temperatures.
  • The worst-case product within the group is expected to be the highest wattage model.
  • The ISTMT report must be conducted at the applicable TMP location on the driver for the product where the driver operating temperature is worst case.
  • If multiple drivers exist within the gamily group, manufacturers are required to demonstrate which driver will result with the worst case with specific and relevant rationale. DLC reserves the right to ask for thermal test data on each unique driver if rationale is not specific enough to demonstrate worst case.
Zonal Lumen Density
  • Provide measurements from tests conducted in accordance with LM-79 (and reported as required for an LM-79 test) for a representative model for each different optical distribution offered in the family group.
  • In house testing is allowed.
Driver Characteristics
  • For each unique driver used within a family group, manufacturers must provide electrical testing for each driver group to demonstrate which driver variation will result in the overall worst case metrics identified under the Independent Test Reports for Family Groups and Sub-groups.
  • In general, this testing should include the input voltage, current, and wattage, the output voltage, current, and wattage, and the THDi and PF, for each loading condition of each driver within the family group. This information should be factored into the scaled performance methodology and identification of “worst case” efficacy and power quality.
  • In-house testing is allowed.