Case Study: Misused Roof Leaders Cause Serious Contamination


With all the things you have to worry about inside your facility when it comes to environmental, health and safety… it’s all too easy to forget about what’s going on with the exterior, especially areas that aren’t easily reached.As they say, out of sight, out of mind.

But it’s serious business, as this means you often don’t see problems until they turn into serious issues that require expensive and lengthy cleanup.

Which brings me to: Have you been on your roof lately? And do you know where your roof leaders (also known as roof drains or downspouts) are located and discharge to?

We worked on a site in the mid-west that had significant emissions from production equipment that were directed to roof vents. Not surprisingly, much of the material discharging from the vents also settled onto the roof.

First off, it’s important to routinely inspect your roof to look for staining, damage, or released materials. For example, if you see pools of oil on your roof near vents, that oil is not supposed to be there, and that means some of your equipment may not be operating properly. You can then inspect your equipment and address the issue. Remember, checking your roof on a routine basis to look for released materials that are not supposed to be there, can assist in avoiding significant equipment downtime issues, and also helps to increase the lifecycle of your equipment by fixing an issue before it becomes a major problem.

Now, don’t forget, if you do find released materials on your roof, it’s important to regularly clean up those materials to prevent them from impacting other areas of your facility.

You might be thinking that if it’s on the roof, why not just leave it up there.

Because Mother Nature has another plan. Wind can blow that material all over the place. But even worse, precipitation can result in even more costly issues.

Imagine this – a facility discharging oil mist onto its roof because some of its processing equipment is not operating properly. That mist settles onto the roof and soon you have pools of oil accumulating near the roof vents. A rain storm occurs. Does that rain stay on the roof? Of course not – roofs are usually pitched in order to direct any precipitation to a nearby roof drain or roof leader that then drains the precipitation off of the roof and into the facility’s stormwater system or even directly onto the ground. Now this particular facility’s stormwater system drained into an earthen swale on its property, and that earthen swale eventually discharged into a pond located on the neighbor’s property. Guess where those pools of oil that were on the roof ended up?

Well, this scenario occurred at our client’s facility in the mid-west. This facility only inspected its roof area when there was a roof leak and they were trying to locate the leaking area. Years and years of oil that was released onto the roof, mixing with precipitation and getting discharged into the facility’s stormwater system resulted in some significant soil contamination in the onsite earthen swale, and even worse, the pond located on the neighbor’s property was significantly impacted. The end result was a cleanup effort that was in excess of $50,000!

That’s bad enough.

But roof leaders can cause contamination issues at your facility even if you maintain a clean roof. Take a look at this picture:

That pipe is a roof leader that is located inside a facility. We often think that roof leaders are located outside a building. But many facilities have these interior roof leaders to drain the central section of the building’s roof. The top of the pipe you see in this photo is connected to a drain located on the roof. The pipe then passes through the floor of the facility and connects to the facility’s stormwater system piping located below the floor of the building. A pretty simple concept; yet a pretty dangerous one also.

You see, what happens at many facilities with interior roof leaders is that facility personnel think these lines are wastewater lines that discharge to the local sewer system. That is what occurred with this pictured roof leader.

In the picture above, do you see the small “L” shaped pipe that is connected to the roof leader? That small pipe is actually a sink discharge line and the sink is located on the opposite side of the wall in this picture. That sink is located in the facility’s Paint Shop and the sink was used to clean paint guns with solvent at the end of every shift. Now, we know that the roof leader is not a wastewater line, but is connected to the facility’s stormwater system, which discharges to an onside pond. Due to this set-up, for years, all of the solvent and waste paint rinsed off in this sink were discharged into that same onsite pond, resulting in a very costly remediation effort that reached into the six figures! (This was a huge Invisible Environmental Gorilla, but just one of the many I’ve identified in a free report you can download here.)

How could something like that happen?

The person who installed the sink assumed it was a wastewater line. We often see miscommunication in these cases.

The people who were there when the facility was first built aren’t around anymore, things aren’t well marked, and that results in current staff not knowing what pipes are used for or where they discharge.

Some facilities simply have “rogue” maintenance folks. Their thinking is that they have been told to install a sink in a specific location. And they’ll look for the easiest place to connect it, no matter where that pipe goes.

A simple step is to identify all of your roof leaders at your facility, determine where they discharge to, and label them “Stormwater Only – No Wastewater”.

If you’re not sure the status of your roof leaders, now’s the time to check them out thoroughly, and we’d be happy to help.

Call Envision Environmental, Inc. now at (609) 208-1885 or email to schedule a call. We can discuss conducting an Invisible Gorilla Evaluation of vulnerable areas at your facility, including roof leaders.

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