Architectural Record BE - Building Enclosure

Choosing Stainless Steel Drains for Caustic Environments

Stainless steel drainage systems provide greater longevity for sustainable wastewater solutions.
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Sponsored by BLÜCHER
Celeste Allen Novak, AIA, LEED AP
Seattle’s Farmers Market Updates Drainage to Stainless Steel
Lightweight stainless steel is easier to install than cast iron. Its high tensile strength allows for long runs of piping.

Photo courtesy of BLÜCHER


Pike Place Public Market is located in the heart of Seattle, with views of Puget Sound. This outdoor/indoor market is over 100 years old and one of the first farmer’s markets. Over 10 million visitors a year visit this historic sight to select fresh fish, drink Seattle’s coffee, and eat from the many food carts and restaurants in the area. From French fries to fried chicken, the challenge for the ancient cast iron system became too much for it to handle. To make matters worse, previous repairs were makeshift and used PVC in place of the cast iron and the entire system was incompatible. In 2008, work began on replacing the ancient drainage.

Pike Place is open 362 days a year and for the small businesses, closing for repairs was not an option. With over 30 restaurants, many opening at dawn and closing for last call after midnight, there was only after hours in the night for project construction. The plumbing contractor, MacDonald Miller Facility Solutions isolated each vendor in the market and used the flexibility and ease of installation of stainless steel to install over 7,600 linear feet of piping in short shifts. In a four-hour shift, the plumbers removed the old cast-iron or PVC piping, installed the new stainless steel pipe and tested it before moving on to the next area of the market. Unlike other types of piping, the installers worked from one end to the final connections using easy to assemble push-fit connections.

MacDonald Miller Facility Solutions provides mechanical engineering, design-build construction, custom metal fabrication, building system service and maintenance. Plumbing superintendant, Kevin Vincent reported that they have had no call-backs to the project in the May 2013 PM Engineering magazine summarizing “As far as we can tell, grease oil and fat don’t stick to it.”3


Choosing Drainage System Components

Some of the basic components of drainage systems are drains, channels, pipes, and fittings. All of these components, many of which are visible in public spaces, can be selected in stainless steel. Although a small part of a large system, more durable selections of each part of the drainage system provides insurance that the entire system will operate for many years as intended.

Drains and Channels

Drains are the most visible component of a drainage system and one that is often subject to heavy traffic and the first flush of any waste component. Floor drains are specified for light- or heavy-weight loading and for light- to heavy-duty flows of waste products. Stainless steel drains should be specified to meet the American Steel and Iron Institute (AISI) 304 or grade AISI 316 depending on location. AISI 304 grades are used both for indoor and outdoor applications. AISI 316 grades are specified for locations that are highly corrosive. These include industrial and marine applications. According to this standard, there must be no significant change and less than 5 percent rust stains in the drain material after 50 years of use.

Stainless steel channels can be installed on most flooring types and work well in kitchens where there can be a high concentration of fats, chemicals, and high heat.

Stainless steel channels can be installed on most flooring types and work well in kitchens where there can be a high concentration of fats, chemicals, and high heat.

Photo courtesy of BLÜCHER

Durable sanitary stainless steel drains can be applied to most flooring types. Details are available from most manufacturers for installations on concrete, tile, vinyl and epoxy flooring. Drains can be placed on vertical or horizontal outlets. They can also be adjustable to meet grade or allow for inconsistencies between the drawings and the actual installation. With tile flooring, stainless steel drains, both round and square drains can be installed with sheet and liquid membranes and leveling compounds.

Choosing Stainless Steel Drains for Caustic Environments

Photo courtesy of BLÜCHER

Additional components may need to be specified as part of the drain such as a surface membrane clamp when installing drains where there is rubberized flooring. When the project is located where there will be a lot of weight placed on a drain, the design professional should also evaluate and specify a reinforced frame for the grate or drain.

The following is a list of just a few of these unique situations and the drains that can be specified to meet the challenge.

• Sanitary floor drains

• Channel drains

• Gastight industrial drains

• Hub drains used for condensate drainage of refrigeration units.

• Marine drains

Pre-sloped shower channel drains, trench drains, and kitchen channels for commercial and industrial applications can be selected in hygienic stainless steel for both standard and customized solutions. These pre-sloped longitudinal drains have a cross fall and provide a sleek and attractive solution particularly for visible areas in medical facilities, hotels, resorts, commercial kitchens, and some industrial locations.

Marine drains are required to withstand some of the harshest waste environments. The location of these drains may require installations on aluminum, plate steel, wood, or resin. Whether specifying a drain, grate for a new, or replacement drain, stainless steel provides the flexibility as a material to be manufactured for all of these unique marine applications.

Drain accessories may include sediment baskets, P-traps, and sand buckets. Drains may require floor clean outs and these can be designed for vacuum handles or nipple pullouts depending on the waste requirements. Vacuum handles allow for tamper proof drains and cleanouts in sensitive environments like test laboratories. Knowing the application will allow the design professional to choose a complete system, one that fits and is easy to install and maintain.

Stainless steel drains can be selected to have patterns or custom designs.

Stainless steel drains can be selected to have patterns or custom designs.

Photos courtesy of BLÜCHER

Stainless steel drains can also be chosen for aesthetics for hotel and residential projects, modular drains can fit within any installation. The latest in drain design includes drains with patterns both historic and modern. Some stainless steel drains can be customized with words or patterns providing an opportunity for commercial branding for the client. For example, branding the drains in a stadium with the home team's logo or on a cruise ship with the company's name can add a unique touch. Specifying for a unique location rather than using an old specification from the last project, will mean fewer change orders and greater success on any project.


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Originally published in Architectural Record