Body Friendly Design The Principles of Ergonomic Kitchen Design
The word "Ergonomics" comes from two Greek words: "ergon", meaning work, and "nomos" meaning "laws". Today, however, the word is used to describe the science of "designing the environment to fit the person, not forcing the person to fit the environment."
What is Ergonomics?
Ergonomics covers all aspects of the human-environment relationship, from the physical stresses body motion places on joints, muscles, nerves, tendons, bones and the like, to environmental factors which can affect hearing, vision, and general comfort and health.
As applied to kitchens, ergonomics looks at the way a kitchen should be designed to optimize movement during meal preparation and cleanup, and minimize the stress on the human body while performing everyday kitchen activities. Kitchen ergonomics is all about prevention.
Ergonomics has been around in one form or another for centuries. But it was not applied to work in the home until the late 19th and early 20th centuries when pioneering home ergonomists began studying kitchen work. In the 1920s Lillian Moller Gilbreth, a psychologist and industrial engineer, began applying rudimentary ergonomic principles to household tasks using time and motion studies. These led to her subsequent development of the kitchen work triangle that became a cornerstone of kitchen design for the next half-century.
In 1925, Katharine A. Fisher, director of the Good Housekeeping Institute, author, and columnist for Good Housekeeping Magazine, began a series of columns around the theme of grouping kitchen tasks according to purpose and materials. Her breakthrough concept was that all things needed to perform a given task — ingredients, implements, spices, bowls and cutlery — should be located where the task was to be performed. Fisher's idea of a "task-centric" workspace is today the single most important element of modern kitchen design.
The world war from 1939 to 1945 gave the science of ergonomics a giant boost when the military began to think in terms of not of just new weapons but new "weapons systems" with ergonomic interfaces that permitted man/machine teams to work together more efficiently. Even before the end of the conflict, these war-time ergonomic concepts were being carried over to, among other things, kitchen design.
In 1944 the President of the University of Illinois at Urbana ordered the formation of the Small Homes Council to research housing issues and apply the principles of ergonomics to kitchen work. By War's end, the Council had already published a number of research findings on kitchen organization which eventually formed the core of the Kitchen Design Rules published by the National Kitchen and Bath Association which today spell out the main guidelines for effective kitchen design.
Then, in the 1970s, kitchen ergonomics got a second big boost. The need to design workable spaces for the persons with disabilities brought it to the forefront again as the Americans With Disabilities Act forced engineers and designers to rethink basic concepts.
Ergonomics is very popular now. People may not know exactly what it means but know that an ergonomic chair, knife handle, or spatula is likely to be more comfortable, easier to use, and often better looking. So, since ergonomics sells, everything under the sun is suddenly "ergonomic".
The Kitchen as Workplace
The kitchen — unlike most other rooms in the home — is a workplace. The job of preparing, serving and cleaning up after meals gets done there. Making that environment fit you is a most critical factor in your satisfaction with your kitchen. Ergonomics aims at making this work more efficient, faster, more pleasant, and less fatiguing by improving the interface between the human body and the things we need to interact with to get work done.
The movement abilities of the human body are the fixed parts of the equation. We are not going to alter the body to fit the environment. So to make work more efficient, we have to alter the environment to fit human movement. We want to minimize movement — eliminating or at least reducing the amount of walking, twisting, lifting, bending, stretching and leaning required to complete a task — and make the kitchen usable by all of the individuals in a household. Every aspect of kitchen design is being given a new, hard look, from countertop heights to the optimum placement of the microwave and dishwasher and the best depth of the kitchen sink.
What good kitchen designers aim for in applying ergonomics to a kitchen is a flexible, adaptable space in which work can be done with minimum wasted motion and maximum efficiency.
Minimum wasted motion not only speeds the work but makes it less fatiguing. Design a kitchen where you'll spend less energy and time bending, walking, twisting, lifting and cleaning, and you'll have more energy and time left for cooking and enjoying.
As early as the 1920s studies showed that merely implementing the basic kitchen triangle to properly locate the major work centers in a kitchen reduced the labor required to prepare and clean up after meals by as much as 70%.
As first discovered by Lillian Gilbreth nearly 100 years ago, movement is minimized if the kitchen is arranged in task centers organized around the three main meal preparation activities: preparation, cooking, and clean-up.
Food preparation takes place at a work surface — countertop or table — that is large enough for the task. Everything required to complete preparation should be right at hand including ingredients and the utensils required to prepare a meal for cooking.
Once the meal has been prepared, it is cooked. The cooking center includes the range, oven, and microwave. Again, everything required to cook the meal should be immediately available: pots, pans, all utensils and the platters and bowls in which the meal will be served.
Finally, once the meal has been eaten, the remaining task is cleanup. This task center is anchored by the sink and dishwasher and, again, includes everything needed for cleanup within the task area.
Ideally, the cook should not have to step away from a task area to complete the task. This ideal is often realized in commercial restaurant kitchens organized around principles of mise-en-place, a French culinary term that translates to "put in place". A busy chef barely does any walking. Everything he or she needs is within immediate reach standing in one place — movement is minimized, efficiency and speed optimized.
A professional workstation contains everything needed to prepare a meal, all within immediate sight and reach of the chef. This means, among other things, that each area may have its own refrigerator, waste containers, sink, cutting area, assembly counter, and warmer.
A lot of this structure is just not needed in a home kitchen. After all, we do not need to prepare any one of twenty entrees, fourteen appetizers or thirty-one desserts at a moment's notice. So our kitchen does not need to be quite so efficient.
But, a lot of the organizational technology of commercial kitchens does translate well to home kitchens and has even been codified by the National Kitchen and Bath Association into Thirty-one kitchen design guidelines. While these guidelines are useful, they do not quite get us to our goal. They describe the average kitchen for a hypothetical average gook. You, however, are unlikely to be perfectly average.
So, a major part of ergonomic design is adapting these general guidelines to you — your height, your reach, your preferred way of doing things, and any physical limitations you may have. Further, there is often not just one user of a kitchen, but several, all with different needs and capabilities. The kitchen has to work well for the snack-getter as well as the main cook and for the beverage-seeker as well as the baker-in-chief.
Adaptability simply means that the space can be used comfortably and efficiently by different users with different requirements and differing capabilities. Are you tall, short? How far can you reach? If you cannot comfortably reach upper cabinets, then you do not want to store most frequently used items there. If you cannot bend to reach lower cabinets, extensive pullouts may be a good option in your kitchen.
Your eyesight is a factor in planning illumination. Studies have shown that a person in his or her 50s with good eyesight still needs 100% more light to read by than that same person in his or her 20s.
Adaptable to Every User
The need to be able to mass produce inexpensively in large quantities has resulted in the standardization of many kitchen components to a hypothetical "average" size. Countertops are, for example, resolutely 36" from the floor. An average height that fits many users but, unfortunately, not every user.
Upper cabinets are installed 18" above the countertop, a location that fits many users. But for very short persons, this means only the lowest portion of the wall cabinet can be reached. After many years of designing kitchens, we have found that a better height for most people is 15-16" above the countertop, a placement that does not interfere with the use of the countertop and puts more of the upper cabinet within easy reach, improving primary storage in every task area.
An adaptable kitchen ignores the standard dimensions and concentrates on making the kitchen fit its user. Countertops can be as low as 32" and still accommodate under-counter appliances such as dishwashers. Upper cabinets can be installed as low as 15" above the countertop and most countertop appliances will still fit.
Kitchens should work for every user, not just the primary user, and certainly not just a hypothetical "average user".
Look at knee space as an example. Designing for persons in a wheelchair requires knee space under the countertop so the individual can get close enough to the countertop to work. Yet, it's also beneficial to other users.
It allows an able-bodied person to sit while cooking or washing up. Sitting while preparing meals is a concept largely foreign to modern homemakers. In modern kitchens, we stand to work. Most provide no seating. Yet sitting helps avoid fatigue and back strain.
Up to the turn of the 20th century, most meal preparation was done while sitting. Meal preparation and cleanup took 8 hours or more of every day in a Victorian kitchen. So being able to sit was a godsend. The work surface was a usually a large, sturdy table at which all of the food preparers sat. (Victorian food preparation was an all-female-hands operation. The wife and daughters all participated. For more information go to Understanding the Victorian Kitchen.)
The very first ergonomic kitchen, the Frankfurt Kitchen designed in 1926 by Austrian architect, Margarete Schütte-Lihotzky, featured an adjustable rolling stool and countertops set at the right height for sitting with ample knee space below. A daughter of the Victorian Era, she could not imagine a kitchen in which food preparers did not sit. Standing while working in a kitchen did not become a widespread practice until Post-war kitchens became so small that there was no place to sit.
The same knee space can be used as out-of-the-way parking for a serving cart, which provides not only a convenient roll-around lowered work surface useful for a myriad of tasks but also a way to set or clear a table in one step-saving trip rather than many.
Safety at the Forefront
Kitchens are inherently dangerous places containing electricity and water in close proximity, sharp objects, flame, and hot surfaces. There is almost unlimited potential for accidents. Kitchens are one of the most frequent sources of fire in the home and are second only to bathrooms as places in which home accidents occur. Yet, as complex as kitchens have become, accidents and injuries are decreasing, in no small part due to better design. And, while ergonomic design is not going to get rid of all of the many causes of accidents, it can help eliminate those caused by unnecessary hazards in the environment.
Kitchen design is largely a process of ensuring that the kitchen structure aids rather than impedes work-flow. Consequently, a major step in every good kitchen design is understanding work-flow: determining what work is being done, by whom, and the process or processes by which it is done.
Since each cook does it a bit differently, the work that occurs in your kitchen is inherently personal. But, while it may sound complicated, work-flow analysis is really nothing more than asking obvious questions. Who will work here, and what work will be done? What motions will be required to accomplish each task? Will you stand or sit while doing these things, and if so, where? What step will follow the initial step in the process, and where will you go for that second step — for the third step?
Work-flow should be orderly and, as far as possible, linear so the cook has everything needed right at hand for each step and does not have to criss-cross the kitchen repeatedly to get the work done. The ultimate objective is to ensure that every bit of kitchen organization and structure — from the physical layout to specific appliance locations to the level of lighting at each task area — helps keep the work safe and efficient.
Issues in Kitchen Ergonomics
A poorly designed kitchen structure affects work efficiency requiring more time and more effort to prepare a meal than should be necessary. Certain elements of a kitchen affect efficiency more than others. Some of the most important include determining the right countertop height and arranging storage for greatest efficiency.
The Right Counter Height
For determining the height of work surfaces, we don't care as much about the height of the user as we do about the distance of his or her elbows from the floor. The elbow is the critical hinge governing all lower arm activity — and it's mostly lower arm movement that does the work in a kitchen.
If the elbow is too high above the work surface, the user tends to lean forward to put your elbows back in an optimal relation to the countertop. If the elbow is too close to the work surface he or she tends to either step or lean back to bring the elbows back into the correct position. In either case, the back suffers.
If after preparing Thanksgiving dinner your lower back is killing you, your countertops are too low. If the pain is in your upper back and shoulders, they are too high. For most people, the standard countertop height of 36" is too low. It was set in the 1930s when people were on average shorter than they are today — and it was probably too low even then. For most cooks, the optimum height is between 37 and 39 inches, and we have made countertops as high as 40 inches.
Your base counter height is found when, with palms on the counter-top, your arms rest at a 45-degree angle to the countertop. For chopping, slicing and most food assembly, this is the optimum height. But different work surface heights better fit other kitchen tasks.
- Hand mixing, for example, should be at a lower level for better leverage and proper ergonomic alignment.
- For washing dishes, the working surface is not the countertop but the bottom of the sink. So, sink depth is the issue. For a tall person, the best depth might be 10 inches but a short person needs a shallower sink to be comfortable, as little as 5" in some cases. How a sink is mounted makes a difference. A 7" sink when undermounted has an effective depth of just over 8" —, the thickness of the countertop become a part of the depth.
- Baking also requires a lower working surface. When rolling out dough, you want to lean forward a little to put your back into the process so your arms and shoulders do not have to do all the work.
- Cooking surfaces are usually set at countertop height. But, many ergonomists believe they should be set lower to make it easier to peer down into pots and pans. How this is done with standard ranges we don't know, since they are always set at about 36" to match the factory standard countertop. With a cooktop, set into the countertop, it's fairly easy to lower the cooking surface by lowering the countertop.
The object of ergonomic storage design is to locate storage so that the things you need to accomplish a task are right at hand — not somewhere across the kitchen and out of reach. Storage design involves three iron rules:
The Iron Rules of Storage1. Store items where they are first used.2. Size storage to the things being stored.3. Store items in a single layer with no item hidden behind or beneath another.
First Use Storage
Every item should be stored at its point of first use. The bowls you use to prepare food should be stored where food is prepared, not across the kitchen with the other bowls.
We tend to store items with like items: bowls with bowls, knives with knives, platters with platters. But that's not how we use them.
Store things where you use them, it saves a lot of walking. If you fill pan and pots for cooking at the food preparation center, pots and pans need to be stored where food is prepared, not where it will ultimately be cooked. The prep area is the point of first use.
Store the things you use most often closest to where they will be used. Anyplace you can reach without moving anything but your arm is your primary storage zone. The most frequently used items go there. An often-used knife should be in a block on or above the counter, not hidden away in a drawer.
Fetching a knife from a drawer requires far too many motions:
- Open the drawer.
- Locate the knife.
- Remove the knife.
- Close the drawer.
You may, in addition, have to step away from the drawer to open it which adds yet more motion to the process.
Ideally, primary storage requires just one motion to locate and retrieve an often-used object. Clearly, we cannot have everything we might need cluttering the counter space but we can have things we use most often right at hand — and everything else close by — with just a little planning.
The primary storage zone is generally in an area between 30" and 60" high for most people and extends laterally about two feet right and left from the center of your body. This zone includes (1) the top two drawers of the base cabinet, (2) the countertop itself, (3) the wall behind the countertop (hang utensils there), and (4) the two lower shelves of the upper cabinet.
Store the next most frequently used items in your secondary zone: (1) The top shelf of the upper cabinet, in the area below the second drawer of the base cabinet and (3) on the lower shelves of adjacent upper cabinets. This is the area you can reach by stretching, bending or stooping without taking a step.
Everything else is tertiary storage — storage you have to walk to or you cannot reach without a step-stool. Only those things used very infrequently should be stored in this zone.
Storage should be sized so that whatever is stored is in one layer — all out in front. In practice that is very difficult to achieve when you only have so much room for your kitchen but it is at least an ideal to strive for.
A drawer should contain just a single layer of things. To hold one layer of silverware, for example, a 3-1/2" or 4" drawer is all the depth you need. For most other utensils, 5" to 7" is adequate. A 9" drawer will hold most bowls and colanders, and a 12" drawer the majority of your pots, pans, and lids (on a lid tray).
Shelving should follow the same pattern — all items in one, single layer. You store dry foods, for example, in four general forms; cans, bottles, boxes, and bags. Cans are seldom larger than 8" in diameter or taller than 8". Can storage, then, is 8" deep and 9" high. Building a pantry 8" deep is a little impractical but it is possible, for example, to heavy up the hinges and hang a can storage rack on the pantry door. Store bottles on the other door on shelves about 12" apart.
Boxes need 14" of depth and bags not more than 16" — so that's the depth of the ideal pantry. But who has enough spare wall for a wide, shallow pantry? So we compromise and use a pull-out pantry — essentially a wide shallow pantry turned on edge then set into a cabinet. It is excellent storage when is kept to a maximum of 18"-24" wide. At this width, every item in the pantry is in view from one side or the other
Where storing some items behind others is unavoidable, use lazy susans and pullouts where possible to bring items in back to the front.
For more information on storage principles, please read Mise-en-Place: What We Can Learn About Kitchen Design from Commercial Kitchens, and for the rules to follow for pantry storage, see Pantry Perfect: The "Can't Go Wrong" Pantry Design Rules.
Appliance designers have come a long way with ergonomic appliance design but still, have a way to go. Dishwashers and microwaves are still the most persistently problematic appliances, with ovens and refrigerators following in close formation.
The dishwasher is an ergonomic disaster. It's much too hard to use. You have to bend and stoop and bend and stoop to load and unload it. You have to spend a lot of time opening and closing the top tray to reach the bottom tray. The bottom-hinged door gets in the way of people moving around the kitchen. It is not a very user-friendly appliance.
Very recently dishwasher manufacturers — starting with the New Zealand appliance company, Fisher & Paykel — have started putting dishwashers in drawers, a much more lumbar-friendly design. Still expensive — twice the price of an equivalent door dishwasher — these are at least heading in the right direction.
Early models seem to have a lot of technical problems and were prone to breaking down. These issues have been largely resolved, but it took several recalls and at least one class-action lawsuit before a generally reliable drawer dishwasher became available.
It's pretty clear that the folks who decided to put the oven below the rangetop never tried to lift a 30 lb. turkey into our out of one. Fortunately, in most household, with the advent of the microwave, the oven is not used as often as it was 40 years ago. But, if someone in your household is a serious, make-everything-from-scratch cook or a fervent baker, a separate wall oven should be considered.
Ideally, the oven door should be waist high, not hugging the floor. A single oven set so the bottom of the oven door is about 32-36" from the floor is the ideal arrangement. If you really need a double oven then expect one or both of the ovens to be either too high or too low.
The trade-off, of course, is cost. You can expect a cooktop/wall oven combination to cost at least twice as much as a range with a built-in oven.
The top freezer refrigerator was never an ergonomic success. It puts the most used part of the refrigerator down by the floor where a lot of stooping and bending is required to use it.
The slight extra cost, however, is almost always justified in a refrigerator which is the appliance used most often in a typical kitchen. For more on cost vs. ergonomic benefits, see Kitchen Remodeling on the Cheap.
The microwave has always been the red-headed step-child of kitchen design. There is just no good place to put one.
Countertop models take up too much valuable countertop space. Under-cabinet units must be small to fit under wall cabinets, ending up too small to be fully useful.
The best solution so far is the under-counter pull-out microwave-drawer. The appliance provides superb access by placing the microwave right at the most convenient height. It can even be installed under a cooktop.
It's not all roses, however. The price is about double that of a premium countertop microwave but coming down quickly as more companies get into the drawer microwave business. And, many models do not have turntables, an astounding omission.
Ergonomic Wall Cabinets
Upper kitchen cabinets (also called "wall cabinets") are somewhat controversial in kitchen design. Many designers don't like them and won't use them. If your kitchen is very small, it will indeed look larger without upper cabinets. Getting along without wall cabinets, however, means your remaining storage has to do double duty. Learn more at Off the Wall Kitchens - Living Without Upper Cabinets.
The problem with upper cabinets is that they have doors. Doors are a nuisance to efficient kitchen work. They keep you from just reaching into the cabinet. You first have to step back to get out of the way, then open the door, then get the item, then close the door again.
One solution is just to omit the doors, turning the upper cabinets into what are in effect open shelves. But doors do have a purpose. They hide all of the clutter and keep dust and grease from getting into the cabinet.
Perhaps the best doors from an ergonomic point of view are those that open upward. Upswing doors are rare in this country; much more common in Europe and Asia. By swinging up, they are out of the way, and can be left open for easy access until the task at hand is done.
Side-hinged doors — by far the most common door type and the only style available in most factory cabinet lines — with modern European-style hidden hinges cannot be left open because they stick straight out and are perfectly positioned to knock noggins and generally be in the way. There are special invisible hinges available that allow the door the lie almost flat against the cabinet but these are large, klutzy, and expensive.
Cost is once again the trade-off. Upswing doors are almost always custom doors and the elaborate hardware necessary to hold a lifted door securely in position is much more expensive than a couple of simple hinges.
More Ergonomics — What We Can Learn from Studying a Commercial Kitchen
If your kitchen does not fit your physical characteristics and your work habits, it may be handsome and fresh but it will not be comfortable, and you won't be happy with it.
While there are good general rules governing kitchen design, they are just that —general— and need to be modified to fit you. Adapting your kitchen to you is a large part of the kitchen design process.
One excellent source of the techniques that work to adapt your home kitchen to your specific needs are studies of what works in commercial kitchens. In a commercial kitchen where a lot of appetizing, attractive and savory meals have to be prepared and assembled quickly and efficiently, everything must not only be ready but within easy reach of the chef. A busy chef does not do much walking. Everything he needs is within his or her immediate reach standing in one place — movement is minimized, efficiency and speed optimized… (Continues).