Specifying Drainage Systems for Efficiency, Performance and Safety
Introduction
In Australia, the market size of the restaurant industry is expected to increase by 5.1% in 2021.[i] As food and dining options grow, so will the demand for commercial kitchen design. The market is not limited to restaurants, but includes kitchens in health and aged care facilities, schools, and food and beverage production facilities, presenting the design and construction industry with a slew of new opportunities.
The success of a commercial kitchen or food and beverage production facility is made or broken on its design. Kitchen design is a vital component in how a kitchen will operate, and how effectively it manages space and budget constraints. A well-designed kitchen will run safely, smoothly and efficiently, ensure consistent performance, and handle heavy commercial workloads.
Drainage design is of special importance but is often an afterthought behind aesthetics and functionality. A good drainage system contributes to food safety, hygiene and cost control, all vital factors in a successful commercial food operation. Conversely, insufficient drainage leads to unnecessary operational costs and, at worst, can result in food contamination and loss of business.
When designing commercial kitchens, off-the-shelf drainage products may not provide the best solution for the very specific needs of each application. A better approach is to understand the installation environment and assembling tried-and-tested systems with the appropriate capabilities, designed into a customised, optimal layout. This will maximise performance and economy by not under or over-engineering while benefitting from systems with proven quality and reliability.
The Importance of Drainage
Commercial kitchens are spaces that are subject to high traffic and regular occurrences of spillage of liquid used during cooking and cleaning, as well as grease, fat and food waste. Without an appropriate drainage system, wastewater can cause pipe blockages, and major disruptions to service. Kitchens must be designed so that any liquids present on the floor or discharged from equipment are quickly and safely removed.
In a commercial kitchen, drainage can impact major aspects of the operation with food safety among the highest concerns. Food can become contaminated if wastewater is not safely drained away during food preparation and when cleaning surfaces. An ineffective drainage system can also make it difficult to complete basic kitchen tasks, such as washing raw food, hand washing, and separating Good drainage systems prevent bacteria from entering into the premises, and reduce the incidence of contaminated water pooling and stagnating.
Commercial kitchens need to operate in a cost-effective manner. Poorly-designed drainage that is difficult to maintain or is prone to blockages will incur additional costs in cleaning, repairs and business disruption. On the other hand, an effective drainage system will improve work efficiency, especially in relation to food preparation and cleaning tasks, reducing labor costs.
Mitigating the risk of injury in a high pressure kitchen is of the utmost importance to the success of a food business. A good drainage system contributes to health and safety by eliminating the risk of slips, trips and falls created by liquid pooling on the floor. Drainage should also enable high levels of hygiene to be maintained on the premises.
Drainage for Commercial Kitchens
Design Considerations
Key Applications
When designing a commercial drainage system, the first step is understanding the key areas in a commercial kitchen or food production facility in which drainage is required, and the different design considerations for each application. This includes the following:
- Storage. Areas in which food is stored and prepared will need to be regularly washed down and may be subject to spillages. Floor drains for storage areas need only handle low to medium flows, but slip resistance and load class will be high priority if goods are moved using trolleys or forklifts. In cold storage rooms, drainage is required to release condensate.
- Preparation. Preparing food typically involves significant water use and results in food waste (peels, off cuts and so on) as well as liquid waste. Efficient surface water removal is needed to facilitate high levels of cleanliness and hygiene.
- Production. The space in which food is produced is subject to high levels of activity during service so protection against slips and falls is required. Spillage is common in such areas, and water is regularly discharged by kitchen appliances during cooking.
- Washing and disposal. In areas involving the removal of residual food, scraping, pre-soaking, rinsing and so on, care must be taken to reduce the buildup of fats oils and grease in drainage plumbing.
In all environments, drainage should be placed in accessible areas to facilitate easy cleaning and maintenance.
Drainage System Considerations
Drain type
The primary function of a drain is the interception of fluids produced in operational or cleaning processes. There are various types of drains, from point drains to linear drains, and different options for gullies and channels, all of which are selected depending on the application. For example, if the system is catering for the emptying of large vats, or there is a risk of a machine malfunctioning resulting in a massive discharge, the drainage system must be capable of handling high volumes of water.
Conversely, if the area is subject to only minimal accidental spillage, you will need a drainage system of the appropriate capacity. If the application calls for isolating designated wet and dry areas, there are specific drainage types that are more effective than others for this intended purpose.
Table 1. Meaning of Terms
| Term | Description |
| Point drain | Grated drain that is typically located in the middle of a floor. The floor is sloped in all directions to ensure water flows towards the drain. |
| Linear drain | A drainage system comprised of an elongated rectilinear channel that is built into the floor. Floors must be sloped in one direction towards the drain so that water is collected and sent to the drain outlet. Also referred to as a “channel drain” or “trench drain”. |
| Slot channel (or slot drain) | Refers to a form of linear drainage that has a channel with a narrower opening that does not require grating. |
| Sump | A basin in the ground that collects wastewater and other liquids. |
| Trap | A U-shaped portion of piping designed to retain a small amount of water that prevents unwanted flow and gases from entering the premises while allowing wastewater to flow through. |
Intermittent or continuous flow
Whether the drainage system must cater for an intermittent or continuous flow will factor into product design, specifically outlet size and quantity along with channel dimensions and sump capacity. Some types of commercial kitchens may be subject to heavy flows during a short service period, whereas production facilities may require capacity for longer work hours.
Efficient surface water removal
Different types of drainage systems convey water quicker than others and, again, your selection should be dictated by the application context. Channel dimensions – width, depth and slope – will influence conveyance rate. Other factors include grating open area (gaps in the grating), sump capacity, gully design, outlet size and accessories such as strainer baskets and traps.
Grate open area and maximum individual open area
Some applications require larger openings to wash down surfaces and catch solids in strainer baskets. For example, butcher shops undergo regular intensive surface cleaning, but meat debris must be prevented from entering the drainage system. Other applications require a large total open area but small individual openings so as to not create a trip hazard (e.g. protecting against heels getting caught) or prevent items being dropped into the drain.
Catchment of solids
Catchment of solids to prevent them entering the wastewater system is often not considered adequately, but fulfils an important environmental function. Strainer baskets can be specified to catch solids from drainage water in different sizes and capacities. There are fixed and removable strainer basket options, as well as double strainer options.
Separating dry and wet areas
Some drainage systems are better than others at preventing liquid from entering adjoining areas. Narrow or slot systems are effective at this task, and are especially suitable for an expected high traffic load. In comparison, gullies may not be suitable unless combined with components that create an effective liquid barrier. If the channel is too large, the large grating area may increase the risk of trips, slips and falls.
Load rating
Grates are designated by classes according to load capacity in accordance with AS 3996:2019 Access Covers and Grates. Choosing a grate with the requisite load class rating for the application is important for safety and longevity. If the area contains heavy equipment, the grate’s load capacity will determine the likelihood of it failing under that load. Other areas may only be subject to foot traffic, so a high load rating is not required.
Slip resistance
All slip resistance standards must be followed for commercial kitchen environments. The drainage system must be tested in accordance with AS 4586:2013 Slip Resistance Classification and its slip rating should be appropriate for the application. Anti-slip grates are available, including designs that prevent heels from becoming trapped. When installing drainage, ensure that the connection between the floor and the adjacent grate does not create an unnecessary trip hazard.
Material selection
In a commercial kitchen or production facility, some drainage systems will come into contact with chemicals or materials that could impact its durability. Accordingly, the grade of stainless steel used for the drainage system will be an important factor in determining suitability. Different finishes, such as bronze, may be used to increase durability and longevity.
Assessing Your Options
Choosing a solution that delivers performance and functionality suitable for the application is critical to a project’s success. Leading manufacturers offer the ability to build “custom” solutions by selecting grate types, lengths, depths, outlet sizes and so on, while the overall design itself is based on tried-and-tested systems. This offers the best of both worlds – proven performance as well as customised drainage layouts that meet project-specific needs.
The ability to customise tried-and-tested systems is important as it reduces the risk that the solution will not perform as expected in the unique conditions in which it is installed. The economic impact of drainage failure on a commercial operation is high, whether it be losses from food contamination, work health and safety incidents or reduced kitchen efficiency. Conversely, there is also the risk of over-specifying – selecting a solution that offers performance and functionality that greatly exceeds what is needed for the intended purpose. Over-specification can result in greater initial expense, as well as increased service and maintenance costs.
Customisable drainage systems can be built to fit the layout and design of your kitchen to exact dimensions. Custom channel units can be designed to surround machinery, there are fewer issues fitting within existing tiling patterns and performance can be tailored to meet all project requirements. The system can be designed to suit the type and composition of flooring being used, maintenance requirements as well as budget.
Allproof
Stainless Steel Drainage Solutions for Commercial Kitchens
Allproof Industries is a New Zealand family-owned manufacturing, marketing and distribution company specialising in plumbing, drainage systems and fire protection products. At the forefront of design, quality and service for the construction industry, Allproof ensures designers and tradespeople alike get the best in innovative and quality products when they need them.
Allproof offers a range of specialised plumbing and drainage solutions for commercial kitchens and factory production facilities. The company’s square or round Storm-series drains come in four grate sizes to suit pipe sizes 80mm, 100mm and 150mm. High quality, durable and long-lasting cast bronze vinyl flanges with clamping systems to fit inside 50mm, 80mm and 100mm pipe risers are also available. The Allproof CK (Commercial Kitchen) sumps, CK strip drains and vinyl clamping channels come in standard or custom sizes.
Allproof’s fully stainless steel commercial slot drain makes an excellent high capacity drainage solution with low surface impact. Strainer baskets can also be specified fixed or removable. The company’s experienced team of technical staff and product designers know the questions to ask, the options to provide and will draw up a system to suit the layout and dimensions of each individual project.
Custom drainage systems are available and manufactured for each project from flat sheets of stainless steel. By owning the manufacturing process from start to finish, Allproof are able to control supply and achieve the highest levels of quality and reliability.
Proven Performance
Allproof has intensive research and development capabilities that cannot be matched by independent fabricators. Beyond design and fabrication, Allproof puts their grates and drainage systems through stringent testing procedures to ensure they meet the company’s exacting standards. For example, the company recently designed a new grate to achieve high slip resistance and load class. This new design was quickly produced inhouse and installed in facility settings to observe its performance under a turning forklift. With their inhouse production facilities at the ready, Allproof’s expert team iterated on the design until it performed sufficiently under real world conditions.
Allproof’s grates and drainage solutions not only undergo inhouse testing in performance categories such as load rating and slip resistance, but they are also submitted to NATA-accredited laboratories for independent testing and certification. Drains with a load class rating of up to Load Class C (5000kg wheel load) are available, and all products have an independently tested and verified slip resistance rating.
All products are designed, developed and manufactured for the Australian plumbing and drainage industry and meet all requirements of sanitary plumbing and drainage under AS/NZ 3500.2.2.
[i] IBISWorld. “Restaurants in Australia – Market Size 2007–2027.” IBISWorld. https://www.ibisworld.com/au/market-size/restaurants (accessed 19 April 2021).
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