4. Illumination During Blackout (incl. Lumen Discussion)

How much illumination do we need in a blackout?

The amount of illumination needed during a blackout depends on the specific activities that you need to perform as well as on the ambient light conditions. In general, it is a good idea to have at least a minimum level of lighting available in case of a blackout, especially if you need to navigate through unfamiliar spaces or perform tasks that require some level of visibility.

Inside a building, you may want to have a flashlight or other portable light source available to help you navigate through the building and perform essential tasks. The required output and intensity of the light will depend on the specific tasks as well as on the available ambient light. If you are in a room with windows that allow some natural light to enter, you may not need as much artificial light. However, if you are in a windowless room or basement, you may need to use a more powerful light source.

Outdoors in an urban environment, the amount of ambient light will depend on the time of day and the level of lighting in the surrounding area. During daytime, there may be enough natural light to allow you to see your surroundings without the need for additional illumination. However, during nighttime or if the surrounding area is not well lit, you may need to use a flashlight to help you see. It is important to use caution when moving around in a blackout, as the lack of lighting can make it more difficult to see hazards or obstacles.

How many lumens?

Flashlights with different lumen ratings can be useful for different tasks and situations. The lumen rating of a flashlight refers to (for our purposes) the total amount of light that the flashlight is capable of producing.

  • 1 lumen would be useful for tasks that require minimal light, such as reading a map or finding your way around a room in dark conditions.
  • 10 lumens would be useful for tasks that require a little more light, such as reading in a tent or finding your way in a low light environment.
  • 100 lumens would be useful for tasks that require more light, such as illuminating a path or signaling for help.
  • 1000 lumens would be useful for tasks that require a even more light, such as illuminating a larger area and/or competing with a lot of light pollution.

As a rule, the darker it is, the less light you need.

It is important to consider the specific requirements of your task when choosing a flashlight, as using a flashlight with too much or too little light output can make it more difficult to perform the task effectively.

In a blackout situation, it is helpful to use a flashlight that is always starting in a lower lumen setting and only increase to higher settings when necessary in order to conserve battery power.

If you could only have one...

If you could only have one single flashlight with a fixed output level, it would be a good idea to choose a level that is high enough to allow you to see your surroundings clearly and perform necessary tasks, but not so high that it drains the battery quickly or causes discomfort or strain on your eyes.

A flashlight with an output level of around 50 lumens (yes, really!) would be a good choice for many tasks. It would provide enough light to allow you to navigate through a dark room or tent, find your way through a dark hallway, or perform tasks that require some level of visibility, without the output being too high or draining the battery too quickly. It would also be suitable for tasks that require a moderate amount of light, such as reading a map or repairing a small object.

Ultimately, the best output level for your flashlight will depend on your specific needs and the tasks that you need to perform. It may be helpful to have a flashlight with multiple output levels to adjust as needed.

Light Discipline

Light discipline is the practice of minimizing the use of (artificial) light in order to reduce the visibility of a location to outsiders. This can be particularly important in emergency situations, where the use of light may attract attention or reveal the location of a group to unfriendly parties. In a blackout situation, it may be necessary to practice light discipline to avoid attracting unwanted attention or revealing the location of a group to outside threats.

In order to practice light discipline, it is required to use light sparingly and only when necessary, and to use low-power light sources and settings whenever possible. This can involve using small, portable light sources such as flashlights or lanterns, rather than large, powerful light sources such as floodlights. It may also be necessary to use lights that are shielded or directed in such a way as to minimize the visibility of the light from outside the location.

Red light

Using red light can be an effective way to practice light discipline, as the human eye is less sensitive to red wavelengths of light. This means that red light is less visible from a distance than other colors of light, and it can be used to perform tasks without attracting as much attention as other colors of light.

There are a few factors to consider when using red light for light discipline. One is the output of the light. Even though red light is less visible than other colors, a high-output red light may still be noticeable from a distance. It is generally best to use a low-power red light source to optimize light discipline.

Another factor to consider is the color of the surfaces that the light will be illuminating. Red light can be absorbed or reflected differently by different colors, which can affect the visibility of the light. For example, red light may be more visible reflected off a white surface than off a black surface.

In summary, using red light can be an effective way to practice light discipline, but it is always important to consider the specific needs of the task and the ambient light conditions when choosing a light source.

Start with the battery

The best flashlight is useless if it needs a special type of battery that is not commonly available in the area of concern. For disaster preparedness, one of the most common sizes and types of battery should power at least one flashlight.

The most common battery size for flashlights include:

  • AAA batteries: AAA batteries are small and lightweight, making them a good choice for compact, portable flashlights.
  • AA batteries: AA batteries are slightly larger than AAA batteries and are often used in mid-size flashlights.

The availability of different battery sizes and chemistries may vary depending on the specific location and the type of store or retailer. In general, AAA, and AA batteries are widely available all over the world. These battery sizes are commonly used in a variety of devices, including flashlights, and are available at many stores, including supermarkets, drugstores, and at electronics retailers.

Battery chemistry

  • Alkaline batteries are commonly available. They are relatively inexpensive and are widely used in a variety of devices, including household applicances where they can be salvaged from, if needed. Alkaline batteries tend to leak and may destroy devices they are stored in.
  • Rechargeable batteries may not be as readily available as disposable batteries in some locations and are of course dependent on outside electricity for recharging.
  • Lithium batteries are often used in high-drain devices such as cameras or handheld GPS units. Quality lithium batteries have the longest shelf life and are therefore suitable for long-term storage. Availability may vary.

It is generally a good idea to have a variety of battery sizes and chemistries in case of an emergency, as different devices require different types of batteries.

Various battery chemistries in low temperatures

Rechargeable batteries can be negatively impacted by cold temperatures and may lose up to 50% of their capacity. To determine the remaining capacity of a rechargeable battery, you can use a digital multimeter to measure the voltage.

In contrast, primary (non-rechargeable lithium) batteries are more resistant to temperature changes. However, measuring the voltage of a primary battery does not provide useful information about how much time the battery has left before it needs to be replaced.

It is always a good idea to bring at least one spare battery with you, no matter the type of battery you are using.

How many batteries to store

The number of batteries that you should have on hand will depend on the specific needs of your household and the devices that you use that require batteries. Some factors to consider when determining the number of batteries that you should have stocked include:

  • The types of devices that you use that require batteries: Consider all devices, such as flashlights, smoke detectors, and remote controls. Make a list of these devices and the types and sizes of batteries that they use.
  • The frequency of use of these devices: Consider how often you use each of these devices and how quickly the batteries are used up. This will help you to estimate how many batteries you will need to ensure that you always have fresh batteries available.
  • The shelf life of the batteries: Consider the shelf life of the batteries that you are using. Some types of batteries, such as lithium batteries, have a longer shelf life than others, so you may be able to stock up on these types of batteries without worrying about them losing their charge over time.
  • Your budget: Consider your budget for batteries and how much you are willing to spend to have a supply on hand.

As a general rule, it is a good idea to have at least a few of each type and size of battery that you use regularly in storage at all times. This will ensure that you have fresh batteries available when you need them and can minimize the risk of being caught without power in the event of an emergency.

Blackout