The Occupational Safety and Health Administration (OSHA) classifies vaults as a confined space, meaning their configurations hinder the activities of employees who must enter into, work in or exit from them. And it’s the last place you’d want to put a backflow preventer.
In many instances, employees who work in confined spaces face a number of risks. Some of those risks are caused by the vault alone, but other risks come with installing the backflow preventer in the vault. That’s why you must take precautions to minimize these risks — especially when it comes to backflow preventer installation.
If you’re installing a backflow preventer and concerned about employee safety, this blog will help you meet occupational safety and health standards. OSHA’s confined space regulations were designed with safety in mind. So, let’s take a look at its standards and find out why your backflow preventer should never be installed in a vault.
What is an OSHA Confined Space?
OSHA’s confined space definition is pretty thorough. It defines a confined space as:
- Being large enough for an employee to enter fully and perform assigned work
- Not designed for continuous occupancy by the employee
- Having a limited or restricted means of entry or exit
These spaces may include underground vaults, tanks, storage bins, pits, and diked areas, vessels, silos, and other similar areas.
Confined Space Dangers
OSHA makes it clear that if you’re working in a confined space, you’re at increased risk of exposure to serious physical injury. These injuries could result from hazards such as:
- Entrapment
- Engulfment
- Hazardous atmospheric conditions
OSHA regulators say confinement itself may pose entrapment hazards. They also note that work in confined spaces may keep your employees closer to hazards (such as machinery components).
OSHA Permit-Required Confined Space
Even if you have a confined space that has a permit, danger still exists. They still contain health or safety hazards. By definition, a permit-required confined space has one or more of these characteristics:
- Contains or has the potential to contain a hazardous atmosphere
- Contains a material with the potential to engulf someone who enters the space
- Has an internal configuration that might cause an entrant to be trapped or asphyxiated by inwardly converging walls or by a floor that slopes downward and tapers to a smaller cross-section
- Contains any other recognized serious safety or health hazards
Even with a permit, you must take precautions to minimize risks. Unfortunately, these precautions can be expensive, take time, and are often not followed. This poses a real safety risk to people inside the vault.
Controlling Hazards in a Confined Space
Some of the things you can do to control the hazards in a confined space can include:
- Specifying acceptable entry conditions
- Isolating the permit space
- Providing barriers
- Verifying acceptable entry conditions
- Flushing or ventilating the permit space
In addition to personal protective equipment, other equipment that employees may require for safe entry into a permit space includes testing, monitoring, ventilating, communications, lighting and rescue equipment, barriers and shields, ladders, and retrieval devices.
In general, to control the hazards in a confined space you need to make sure you have (at the very least) these four areas covered:
- Gas Detection
- Fall Protection
- Ventilation
- Communication
The atmospheric conditions of confined spaces must be tested prior to entry and continually monitored. It goes beyond sniffing for oxygen or sniffing to be sure it’s not an explosive environment.
You must also use a safety harness before entering. Authorized entrants who enter a permitted space must wear a chest or full-body harness with a retrieval line attached to the center of their backs near shoulder-level or above their heads. And have a person to hold the harness rope and pull out the entering person if there is trouble.
Vaults and Backflow Preventers Don’t Mix
Because of the added costs, most vaults are not considered permit-required confined spaces. However, the municipality can put that into its local code. This would then require workers to have a permit to open them and also may require signage.
A backflow preventer in a vault must be tested each year. That means the tester must climb down into this confined space, and we see this as a clear problem. It’s unfortunate, but the utility vault has been the standard for backflow design for several decades. By installing your backflow preventer in an outdoor, above-ground enclosure, you can eliminate the risk.
The Best Place for a Backflow Preventer
Outdoor, above-ground enclosures come with panels that are detachable. The entire length of one or more sides of your equipment enclosure can sometimes be made of removable access panels. This makes it easier to maintain and test your equipment.
A removable panel will also be placed in front of your control panels. If the panel is not removable, it will instead be hinged. This provides continuous, easy access, which is critical, especially for a backflow preventerbecause they must be tested regularly. Fire sprinkler systems must be tested weekly.
Newer outdoor backflow enclosures have a roof that can be lifted or removed altogether. This makes it easier to get to your equipment if it ever needs to be replaced.
You can also customize your enclosure design to fit your needs and base it on the size requirements of your equipment which means a custom enclosure may be less expensive than a standard one. A standard enclosure may contain too much space for your equipment.
And if you’re worried about aesthetics—don’t be. You can even blend your enclosure into its surroundings.
An outdoor above-ground backflow enclosure also eliminates flooding risks. Because it’s already outside the building, if your backflow preventer begins to dispel water, everything inside will be safe.
Yes, we know a change in any industry can be hard. But we believe the protection of clean water, safety, and the owner’s best interest should be enough to convince you. There is evidence that the best practice of using an above-ground enclosure should replace the vault.
The civil engineering community has been implementing many other changes over the years when a better design presented itself. Make your next project the one where you will make this change. Please call us if we can provide support or help you with your next project. Or check out our free guide “Trends in Backflow Preventer Installation.” It will thoroughly explain why your installation should be in an enclosure and not in a vault.
