Portland Kettle Works

Brewery Tanks: The Shadow Condition – Side Manway vs. Top Manway

Brewery Tanks: The Shadow Condition – Side Manway vs. Top Manway

Brewery Tanks Blog No. 1

The Shadow Condition – Side Manway vs. Top Manway

Which is best for my brewery?

Remarkably, a surprising number of new brewery owners tell us “all brewery tanks are created equal”. In the world of brewery tanks, there are design and engineering details that collectively differentiate a quality tank from a merely adequate or totally awful design.  What exactly makes a fermentation vessel and brite tank work, and how do differences in engineering effect safety, operations, and tank and process efficiency in your brewery?  If you believe a tank is a tank, and haven’t answered these questions, it’s a great time to take a closer look at the under appreciated brewery tank.

Why a manway?

With the installation of a manway during fabrication welders and finishers can access the interior of the vessel as they weld, fuse, blend, finish and ultimately inspect the interior surfaces.

Without the manway there would be no practical way to fabricate a brewery tank.

PKW Side Manway

After fabrication the manway serves as an inspection port, hop and adjunct addition port and dangerously can make your tank safety liability and an OSHA classified Permit Entry Confined Space.  When considered in this light, the brewery tank would arguably be better off if it prevented access or were sealed permanently.

Remember the Grundy?  Beloved and maligned, these tanks are more or less permanently sealed after fabrication leaving the brewer with a very basic yet effective brewery tank without a manway.  Every modern brewery tank design I know of incorporates either a top or side stationed manway.

The following exploration of the manway design, position and intent will help resolve what will work best in your operation.

Is your brewery tank a confined space?  – Yes

A confined space:

– Has limited or restricted means of entry or exit,
– Is large enough for an employee to enter and perform assigned work, and
– Is not designed for continuous occupancy by the employee.
Why consider a top mounted manway? – Safety

Our welders build these tanks with a great deal of safety in mind.  They are trained and have a buddy system to check their status when working in the tank.  Most breweries are not so fortunate.  Oftentimes it may be a one-man operation.  By putting the manway on the top it becomes an extremely difficulty entry point, which is exactly the point.  As a new brewer once put it, “How am I going to fit my fat ass in through that manway?”, my answer is and always will be, “You don’t.”

From a liability standpoint, eliminating access to confined spaces is good business.  Side manways invite entry.  Top manways prevent entry.

Shadowless, Semi-Shadow and Shadowed Tank Design

Do you like washing the dishes?

Every side mounted manway in a brewery tank is a hassle, as the unsanitary condition it creates must be hand scrubbed every time the tank is cleaned.  A minute amount of funk left in the tank will compromise quality of your beer.  Thoughtful tank design and engineering demands use of quality manways that install flush to the tank wall, or preferably in the tank head where the shadow condition is entirely eliminated.   The images below depict common manway designs and installations.

Bad Side Manway

This manway is inferior in quality and design.  It lends itself to a fully shadowed installation and will be a continuous headache, as it serves no purpose other than being a tank component that requires vigorous manual cleaning.  There are no redeeming qualities to this manway and tank design, other than that the tank cost was probably low.

Condensation Side ManwayA better option; Semi-Shadowless Manway

Pros

– Better engineering than Shadowed Design,
– Easier Cleaning than Shadowed Design.

Cons

– Opens OSHA scrutiny for permit confined space safety exposure,
– Manway is installed below the liquid level and susceptible to contamination,
– Does not completely eliminated shadow condition,
– Requires routine hand cleaning and inspection,
– Does not allow dry hopping during fermentation,
– Condensation around manway indicates thermal inefficiency,
– Manway interrupts glycol jacketing reducing tank efficiency.

PKW 7Bbl Tanks at BTU Brassiere

PKW 7Bbl Tanks at BTU Brassiere

The best option – Top of Tank Manway Installation

 Pros

– Eliminates the possibility of tank entry and associated OSHA compliance issues,
– Eliminates the risk of a shadow as its position at the top of the tank is truly shadowless,
– Manway is above the liquid level greatly reducing the possibility of contamination,
– Allows for dry hopping and adjunct addition and can be equipped with a hop hook,
– Allows for complete and un-interrupted glycol coverage greatly increasing glycol coverage and efficiency.

Cons

Requires a ladder to access, not considered a major issue by most brewers as pressure-relief-valves and rupture discs mounted on top of the tank can be serviced simultaneously with the manway.

Please feel free to contact us to discuss the information presented here in more detail.  Happy Brewing!

Cheers!