Valostore's VALOLAB - Introduction

Valostore's Light Laboratory

At Valostore's light laboratory, we can accurately determine the characteristics of various auxiliary lights, handheld flashlights, headlamps, work lights, and other light sources. The light laboratory is located at Valostore's facilities in Limingantulli, Oulu, Finland. We continuously measure and analyze lighting products on the market, aiming to provide independent measurement data to support our purchasing department, product development team, and customers’ buying decisions. With the best equipment on the market, our customers can trust that the information we provide about our products always reflects reality. Customers are always welcome to visit our laboratory to learn more about our measurement equipment and testing procedures. The best time for visits is on weekdays between 10:00 AM and 4:00 PM.

In this article, we introduce our light measurement equipment and explain the meaning of the following concepts:

• Luminous flux
• Beam distance
• Runtime
• Color temperature
• Color rendering index (CRI)
• How measurements are conducted

Equipment

Our light measurement system consists of multiple specialized devices, with the most important being SSL BTC-20 – Beam Pattern Testing System and Labsphere FS2 – Integrating Sphere. Both devices are specifically designed and developed for our testing purposes, meeting the latest light measurement and quality standards.

SSL BTC-20 – Beam Pattern Testing System

The Valolab BTC is a beam pattern testing system that enables 3D modeling of light beam shapes, along with various other optical characteristics. The system can simulate how a light beam is projected onto a roadway based on installation height and angle. This allows us to recommend the most optimal lighting solutions for different applications. This system fully complies with the ANSI/NEMA FL1 measurement standards and ensures high accuracy in light measurement.

Key Components of the System:

• Luminance Camera
• Spectrometer
• Measurement Rail System
• Projection Screen
• Standard Light Source (used for system calibration)
• Precision Power Supply
• SSL BTC-20 Software

With this equipment, we can analyze multiple characteristics of light sources, including:

• Beam shape (cd)
• Isolux curves (lx, m)
• Luminous flux (lm)
• Runtime
• Maximum beam intensity
• Beam distance
• Light distribution
• Color temperature
• Color rendering index (CRI)
• And more

Labsphere FS2 – Integrating Sphere

The Labsphere FS2 is a U.S.-manufactured light measurement system specifically designed for flashlight testing. The cost of this equipment, including shipping to Finland, is approximately €30,000. This system fully complies with the ANSI/NEMA FL1 standard for integrating sphere measurements.

Key Components of the System:

• 20-inch integrating sphere
• Auxiliary lamp for absorption correction factor calibration
• Standard light source for system calibration
• Precision power supply
• Spectrometer connected to a computer for data analysis

With this equipment, we can precisely measure various light source properties, including:

• Luminous flux (lumens)
• Color temperature
• Color rendering index (CRI/RA value)
• Light spectrum
• Chromaticity
• Runtime & runtime curves
• And more

Luminous Flux (Commonly Referred to as "Light Output" or Lumens)

We measure luminous flux in accordance with the ANSI/NEMA FL1 standard, with one minor deviation: instead of testing three separate units, as required by the standard, we typically test one or two units. This saves time while still providing reliable and comparable results.

Before measuring any light source, the measurement equipment must be calibrated to account for absorption—the loss of light due to reflections and absorption by the lamp body itself. Due to the nature of integrating sphere measurements, some photons do not reach the sensor and are instead absorbed by the lamp housing or measurement aperture. To correct for this, the integrating sphere includes an auxiliary lamp, which allows us to precisely calculate and compensate for absorption losses.

How ANSI/NEMA FL1 Measures Lumens

One key characteristic of the ANSI/NEMA FL1 standard is that luminous flux is measured after the lamp has been turned on for 30–120 seconds.This means that lumen values measured with this method are often lower than the lamp's absolute maximum output. For LED lights, it is common for the initial brightness to be higher immediately after switching on, before stabilizing as the lamp heats up. By allowing the lamp to run for a short period before measurement, we obtain more practical and realistic lumen values that reflect actual usage conditions.

Beam Distance

The beam distance refers to the range at which the illuminance drops to 0.25 lux. This level of brightness is roughly equivalent to the illumination provided by the moon on the Earth's surface during a clear moonlit night. We measure beam distance using the SSL BTC-20 measurement system.

According to the ANSI/NEMA FL1 standard, the beam distance is determined by measuring the brightest point of the beam after the light has been turned on for 30–120 seconds.

Runtime

Runtime is a relative concept, as most flashlights do not maintain the same brightness level for the entire duration of their operation. Instead, luminous flux gradually decreases as batteries or rechargeable cells lose power.

According to the ANSI/NEMA FL1 standard, runtime is considered finished when the luminous flux drops to 10% of the initial measured lumen value.

Below are example runtime curves for some LED flashlights:

Runtime Analysis

As seen in the example runtime curve, brightness does not remain constant throughout the measurement period. In this specific case, light output drops sharply around the 48-minute mark.

However, according to ANSI/NEMA FL1 measurement guidelines, runtime is defined as the time until the luminous flux reaches 10% of its initial maximum value. To determine runtime, luminous flux is measured every minute, and the results are used to generate a graph. The official runtime value is then determined directly from the measured curve.

Color Temperature and Color Rendering Index (CRI/RA Value)

Color temperature and color rendering index (CRI/RA) are not included in the FL1 standard. However, because this information can be useful in some cases, we have chosen to measure and report these values.

Measurements are taken under the same conditions as maximum brightness, with the light operating at full power. In some flashlights, these values may vary slightly between different modes, but the maximum power measurement provides a good general indication of the light’s color properties.