Frequently Asked Questions
Common Questions about SteriPEN
What is ultraviolet (UV) light?
Ultraviolet light is invisible, high-energy light.
Wavelengths of light are measured in nanometers (nm). A nanometer is one billionth of a meter. Visible light ranges from red at about 700nm to violet at about 400nm. Normally the human eye does not see light at wavelengths outside of this 400nm to 700nm "visible" range.
The entire band of UV light is about as broad as the entire visible spectrum - it runs from 400nm to about 100nm. The UV band is divided into 3 ranges: UV-A between 400nm and 320nm, UV-B between 320nm and 290nm and UV-C between 290nm and 100nm. Most of SteriPEN's light is emitted at 254nm, in the UV-C range.
How does UV purify water?
UV light destroys DNA and thereby prevents microbes from reproducing.
Germicidal UV light - between about 240nm and 290nm - acts on thymine, one of the four base nucleotides in DNA. When a germicidal UV photon is absorbed by a thymine molecule that is adjacent to another thymine within the DNA strand, a covalent bond or dymer, between the molecules is created. This thymine dymer prevents enzymes from "reading" the DNA and copying it. Without the ability to replicate DNA, the microbe cannot reproduce and is rendered harmless.
Is UV light dangerous?
Exposure to ultraviolet light can cause skin and eye damage. Used as directed, SteriPEN will not cause UV exposure to the user. Note that SteriPEN's lamp emits a number of wavelengths, some of which are in the visible range. The visible blue light given off by SteriPEN is just that, visible blue light - not ultra violet - and it is not dangerous to look at. In fact while the visible light has no germicidal effect, it is an important indicator that the lamp is functioning properly. If no light is visible the lamp is malfunctioning.
UV-C will not pass through most materials. Drinking containers made from glass, ceramic, metal, and nearly all plastics block UV-C transmission. Also, the underside of the air/water interface in a water container acts as a very effective reflector for UV-C. As a result, when SteriPEN's lamp is immersed in virtually any drinking vessel, the UV-C is well contained. Note that SteriPEN's water sensors prevent it from operating unless the lamp is completely immersed.
While very few materials are transparent to UV-C, there are a small number of uncommon materials that are. These include optical grade quartz (the SteriPEN lamp material) and a few fluoropolymers in the Teflon family - both unlikely materials to be used for drinking containers.
How does SteriPEN operate?
SteriPEN has an onboard microcomputer that controls dose times. The user must decide on one of two volume ranges to be treated - either 16 oz or less or between 16 oz and 32 oz. Once volume has been indicated by either one button push or two, SteriPEN automatically delivers the appropriate dose duration and then shuts off. There is no need for the user to time anything.
SteriPEN's dose time ranges from 38 to 48 seconds for 16 ounces to 90 seconds for 1 quart (or 1 liter). This is far faster than chemical treatments that can take up to 4 hours. SteriPEN is also generally quicker - and certainly far easier - than pump filters. It is also worth noting that SteriPEN's speed and ease of operation makes it useful in places where filters and chemicals are inappropriate such as restaurants and cafes.