Oxygen deficiency in humans can be caused by a medical condition, or by breathing in an oxygen-deficient atmosphere like an enclosed space. In both cases – lack of oxygen is dangerous.
When most people imagine lack of oxygen, the first dangers that come to mind are drowning, submarines, airplanes or caves. But unless you swim regularly, the chances are you’ll never experience any of these.
The reality is that if you are healthy you are more likely to be incapacitated by oxygen deficiency as the result of a stored gas leak.
What is Oxygen Deficiency?
Effects of Various Oxygen Levels
|20.9%||Normal - fresh air|
|19.5-20.9%||Acceptable low oxygen (OSHA)|
|10-19.5%||Increased breathing rate, accelerated heartbeat, impared thinking and coordination|
|6-10%||Nausea, vomiting, lethargy, leading to unconsciousness|
|< 6%||Convulsions, cessation of breathing, cardiac arrest.|
What are Stored Gases?
Stored or industrial gases are a group of gases that are used in businesses and industry. They include nitrogen, oxygen, carbon dioxide, argon, hydrogen, helium and acetylene, as well as small quantities of other specialty gases.
With the exception of oxygen, all the gases are asphyxiates. An asphyxiate gas is a nontoxic or minimally toxic gas which reduces or displaces the normal oxygen concentration in breathing air. Breathing of oxygen-depleted air can lead to death by asphyxiation, or suffocation.
Stored Gases are Everywhere
Have you ever walked into a restaurant? That big aluminum tank on the side of the building is liquid carbon dioxide, or CO2. It is used to carbonate your beverages. CO2 tanks are used in data centers for fire suppression systems. If you’ve ever taken a cruise, ships use them to fight fires too. In addition to oxygen, your local hospital has tanks of CO2 and medical liquid nitrogen installed on every floor.
Do you work in a factory? Welding is done using stored tanks of argon, CO2, hydrogen, nitrogen and helium. Even modern grocery stores are switching to CO2-based refrigerants to keep their meat, dairy and frozen food isles cold.
Need to get an MRI? That machine relies on liquid nitrogen and liquid helium to cool the magnets to -330°F (-203°C). Your dermatologist and local cryospa uses the same stored gases too.
How much stored gas is around you? The market for CO2 gas alone was 32,844 thousand tons of liquid CO2 produced in 2019. The industrial gas market for all stored gases is expected to grow by over 5% annually.
While you may not see them, throughout the day a tank of stored gas is nearby.
Stored Gas Tanks are Safe
The problem isn’t the tanks these gases are stored in, which are designed to strict government regulations. And small amounts of any pressurized gas are not harmful, especially when they can quickly mix with fresh air.
However, a leak in a pressurized gas line indoors can easily become dangerous. For example, one liter of liquid nitrogen vaporizes to 696.5 liters of nitrogen gas at room temperature. For most common gases the expansion ratio from liquid to gas is between 700 and 900. This means that even a small leak can quickly lower the oxygen level in an enclosed room or area.
The challenge is that people can make mistakes. No matter how much training they receive, eventually someone will turn the wrong valve, not tighten a fixture, or cut a hose.
Oxygen Deficiency Alarms
The good news is that with the growing use of stored gases, state and local governments are developing new procedures to audit their use. Building inspectors across the country now require oxygen depletion alarms in rooms containing tanks of stored gases.
For example, an oxygen depletion safety alarm monitors the oxygen level in in a room in real time so that a leak will be noticed before it results in a dangerous situation. In addition, the alarm can control ventilation fans or can be connected to a facility’s HVAC and/or alarm system. In the case where CO2 is stored, a CO2 level safety alarm should be used.
The benefits of stored gases are numerous. From improved medical procedures to fire prevention to even the bubbles in the beer and soda we drink, we can all appreciate the benefits of stored gases. It’s also important to know that with the benefits comes a small risk that should not be ignored.