IKEA AKURUM in Human Factor

IKEA AKURUM in Human Factor

By Szuchi Wang, 2013

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Aims And Objectives

The aim of this case history is to highlight key human factor areas that the height and fitness of working surface in IKEA’s product, AKURUM. In this report, how AKURUM working surface height affect users’ physical condition, safety and working efficiency would be analysed, based on which, some enhancement would be carried out in the end of the report. The versatile, flexible AKURUM kitchen system is the foundation in all IKEA’s built-in kitchens. It's a frame system that allows users to make exactly the kitchen they want. The themes discussed are as follows: 0. Aims And Objectives 1. Background 2. Kitchen Worksurface Problems 3. The Work Area Fitness 4. Muscle and Skeletal Problems 5. AKURUM Storage Height 6. Cognition of Manual 7. Suggestions & Conclusions 8. References

Souce: IKDO_Custom Designed IKEA Kitchens

1

Background

Normal living spaces in big cities are quite small, average flat size is around 70m² in London, and the kitchen size is just 7.65m² (Nationwide, 2008), which is a small place for a huge amount of works to be done. Besides stylish and fashion, the most important things of kitchen are efficiency and safety, if the hight of kitchen countertop is not designed properly would lead to heavy backache to users, even causing more serious accidents. In a previous issue of Applied Ergonomics (Ward, 1970) it was stated that "investigations to determine the amount of physiological effort (particularly that of muscle activity by techniques such as electromyography) are needed in order to ensure that the housewife performs her tasks with the minimum of unnecessary effort and maximum satisfaction..."

Lambeth, London

Living

Kitchen

Bedroom1

Double Single Bedroom Bedroom

Souce: Housing Space Standards August 2006

Souce: Housing Space Standards August 2006

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Kitchen Worksurface Problems Arising from the confirmed high incidence of illness and other signs and symptoms, estimations were made of the loading on the muscular and skeletal systems of kitchen workers.

The symptoms were confirmed to be associated with the raised position of the upper limbs caused by working surfaces which were too high (Applied Ergonomics, Ward, 1970).

• The worktable with the cutting board was too high for a third of the workers, estimated from individual elbow height (Applied Ergonomics, Ward, 1970).

• 34-80% of the kitchen equipment was too high. Raising loads above shoulder level into ovens or pressure cookers, for example, loaded the shoulder joints (Applied Ergonomics, Ward, 1970).

• The back was loaded especially in lifting to knee height and in continuous standing (78% of working time) (Applied Ergonomics, Ward, 1970).

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The Work Area Fitness

For most of the 20th century, kitchens were organized around what's known as the work triangle — the geometry determined by sink, range and refrigerator. A good design will make the distances between them comfortable, if they're too short, the work area will be cramped; if too far, the cook will become worn out trotting between them. The rule of thumb is that the three legs of the triangle should add up to between 12 and 26 feet. The work triangle influence not only the safety issue but also the efficiency while working (SFS, 1974).

Souce: Housing Space Standards August 2006

The standhig position was used as the measurement basis for the kitchen working surfaces, for this standing position was adopted for 78% of the working time. In the new kitchens the working surface height was in accordance with the 900 mm standard (SFS, 1974). In the old kitchens the working surfaces could be lower (850 mm). The height of the cooker was normally the same as that of the working surfaces: the average cooker height was 880 mm (840- 910 mm).

Souce: IKDO_Custom Designed IKEA Kitchens

While designing the work triangle, the essential thing to consider is the size of each working section (sink, range and refrigerator), which is based on the working area of normal people. Take IKEA AKURUM sink cabinet for example, right-handed users would need at least 8” on the right side with unprocessed dirty dishes or food, and 24” storage for clean dishes and processed food (Ma¨kela¨ and Helio¨ vaara 1991; Urwin et al. 1998; Coˆ te´ et al. 2000; Picavet and Schouten 2003; Ijzelenberg and Burdorf 2004).

• The dashed lines in the diagram represent where most frequently used area are placed in relation to the countertop (Gao et al, 2010).

• Ergonomically optimum control panels should be within the visual range, which from the diagram is 110° (Gao et al, 2010).

55°

55°

Souce: Gao et al, 2010 Souce: IKDO_Custom Designed IKEA Kitchens

• For determining the height of work surfaces, it is no need to care as much about the height of the user as the distance of his or her elbows from the floor. The elbow is the critical hinge of all lower arm movement — and it's mostly lower arm movement that does the work in a kitchen (Coˆ te´ et al. 2000).

Souce: Housing Space Standards August 2006

• Fit the countertop height to the actual user, not a hypothetical “average” user. This mean countertops as low as 32” and as high as 40” above the finished floor — and not the standard 36” (Coˆ te´ et al. 2000).

• Loading can be modified by fitting the kitchen with working tables which are adjustable for height (800-950 mm) and by lowering kitchen equipment as follows: cooker height 650 ram, cooking vessel rim height from the floor < 900 mm, oven and pressure cooker rail heights 500-1400 mm (A. Pekkarinen* and H. Anttonen, 1988).

Souce: IKDO_Custom Designed IKEA Kitchens

• 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 (Tuomi et al, 1985). IKEA AKURUM has different size of cabinet legs for users to choose the most suitable height.

• Hand mixing, for example, should be at a lower level for better leverage and proper ergonomic alignment (SFS, 1974).

• Baking also requires a lower working surface. When rolling out dough, users want to lean forward a little to put their back into the process so their arms and shoulders do not have to do all the work (Seppala et al, 1980).

• 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 regarding 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 (Arbetarskydds-styrelsen, 1982).

(Ng, 1993)

(Ng, 1993) Souce: A. Pekkarinen and H. Anttonen, 1988

Souce: Housing Space Standards August 2006

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AKURUM Storage Height

The object of ergonomic storage design is to locate storage so that the things users need to accomplish a task are right at hand — not somewhere across the kitchen and out of reach. Storage design involves three core principles (Coˆ te´ et al. 2000): • Items should be stored where they are first used.

• Size storage to the things being stored.

• Store items in a single layer with no item hidden behind or beneath another.

Using the bio-mechanical model, the loading on different parts of the body when lifting a 12-kg container to different heights in an oven or pressure cooker was examined (picture below). When the container was lifted to above shoulder height, the force moment on the shoulder joint increased by 42% compared with a lift to waist level. In lifting to knee height, the lumbar compression doubled compared with a lift to waist height. Thus rail heights to ovens and pressure cookers affect loading.

The best lift height is at waist level. Ovens should not be situated on top of each other, but side by side. The rail heights should be between 500-1400 mm from the floor (A. Pekkarinen and H. Anttonen, 1988).

IKEA AKURUN design guild suggest that install microwave at 1487.5mm height, which is the shoulder height of average users to heve the best supporting power of body when reaching for higher items (AKURUM_Buying_Guide, 2010).

IKEA AKURUM display:

Souce: IKDO_Custom Designed IKEA Kitchens

In Salonen and Heinsalmi’s report at 1979 of 200 participants, short workers complained more often about neck-shoulder problems than taller workers.

Problems in the neck-shoulder region have been confirmed to be related to a raised position of the upper limbs (Salonen and Heinsalmi, 1979). In evaluating working height on the basis of elbow height and work movements in kitchen work, it was confirmed that the working surface with the cutting board was too high for one-third of the workers. Kitchen equipment was too high for 34-80%.

Working at too high a level is associated with raised upper limbs and this leads to neck-shoulder region problems.

• The achievement of a suitable working height demands the possibility of adjusting the working surface height between 800-950 mm (A. Pekkarinen and H. Anttonen, 1988).

• IKEA AKURUM cabinets height 34 1/2”(876.3mm) without legs, to 36”(914.4mm) topest with legs, suitable for 75% normal users (Grandjean, 1981).

Kitchen Counter Height Preference of 194 participants (Hiroshi MORISHITA, Keisuke WATANABE, Takeru KUROIWA, Taketoshi MORI, Tomomasa SATO,2003).

IKEA AKURUM display:

Souce: A. Pekkarinen and H. Anttonen, 1988 The percentage of working surfaces which are either too high or too low.

(Number of participants)

Souce: A. Pekkarinen and H. Anttonen, 1988

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Muscle and Skeletal Problems

Kitchen workers are mostly women with a high physical workload (Oze 1984a; Pekkarinen and Anttonen 1988). Very little systematic research has focused on this occupational group. In a nationally representative study in Finland, kitchen aids had an increased risk of low back disorders leading to hospitalisation (Leino-Arjas et al.

2002). It seems reasonable to assume that kitchen workers have a high occurrence of even other musculoskeletal pain problems, and further that these cluster by anatomic area.

When the symptoms were primarily classiďŹ ed into three larger anatomical areas, i.e. axial (neck and low back), upper limbs and lower limbs, axial pain was the most prevalent (80%) followed by the upper limbs (58%) and lower limbs (52%). Within one anatomical area, often more than one pain site was mentioned. For instance, among workers with axial pain (n = 394), 52% reported concurrent pain in the neck and in the low back and 44% of those with upper limb pain (n = 285) had concurrent pain in the shoulders and in the forearms or hands (Eija Haukka et al. 2005).

(Number of participants)

Occurrence of concurrent musculoskeletal pain in three anatomical areas among women in kitchen work (axial: neck and low back combined) (Eija Haukka et al. 2005)

(Eija Haukka et al. 2005)

Co-occurrence of musculoskeletal pain among women in kitchen work. Conditional proportions (Eija Haukka et al. 2005)

Conditionally on the occurrence of pain in an index site, the chart reports the proportions of subjects with pain in each of the other sites. For example, among workers with neck pain, only 9% did not have pain in other sites, while 61% reported concurrent pain in the forearms or hands, 58% in the low back, 44% in the shoulders, 36% in the ankles or feet, 34% in the knees and 24% in the hips (Eija Haukka et al. 2005).

In Salonen and Heinsalmi’s report at 1979 of 200 participants, short workers complained more often about neck-shoulder problems than taller workers. Problems in the neck-shoulder region have been confirmed to be related to a raised position of the upper limbs (Salonen and Heinsalmi, 1979). In evaluating working height on the basis of elbow height and work movements in kitchen work, it was confirmed that the working surface with the cutting board was too high for one-third of the workers. Kitchen equipment was too high for 34-80%. Working at too high a level is associated with raised upper limbs and this leads to neck-shoulder region problems.

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Cognition of Manual

• IKEA started using pictorial forms to represent each step of the instructions. By using pictures instead of instructions, IKEA have localised their instructions in true nature. Spread over 4 continents, IKEA would have to provide instructions manuals in around 100 different languages. Illustrative pictures reduce the need for translating these instructions and they make it easier for people to follow the assembly instructions of their new furniture (Claudia Amendola, 2012).

• Based on mental workload graph and Hick’s Law, the relationship between reaction time and the number of choices is a linear function of the logarithm of the number of options the person has to choose between (Hick, 1952; Usher, Zeev, & McClelland, 2002), IKEA AKURUM’s manual provides one simple step only by picture per page for users to follow, gives low mental workload to users, reduce the rate of human error and lapse to happen (Prof. Joseph Giacomin).

IKEA AKURUM’s manual:

Souce: akurum-base-cabinet-frame

Mental Workload:

Source: Prof. Joseph Giacomin

Hick’s Law:

Souce: Friedrick Merkel 1885

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Suggestions & Conclusions

Suggestions:

• The working level can be lowered by using thinner cutting boards. Short workers especially may use a platform as an aid to adjust for their lack of height.

• In kitchen work, loading of the back is affected by continuous standing in addition to low lifting. One seated workplace should be arranged where light cutting, peeling and cleaning work can be carried out. A seated workplace requires sufficient foot space under the working surface and a working chair with height adjustment and adjustable back-rest. A foot support is recommended in seated working at the kitchen work surface.

• IKEA should build up a more detailedly measurement to customize the counter top which should be high enough so that with users’ hands placed flat on the counter, their elbows are bent about 45 degrees.

Conclusions: • If one kitchen does not fit users’ physical characteristics and their work habits, it may be beautiful and fashion, but it will not be comfortable, and users won't be happy with it. While there are good general rules governing kitchen design, they are just general and need to be modified to fit the users.

IKEA provides one excellent source, AKURUM, which adapt users’ home kitchen to their specific needs, mainly based on the elbow height so that some muscular and skeletal harms can be avoided.

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References

Arbetarskyddsstyrelsen. 1982, Restauranger och andra storhush~11. Arbetarskydsstyrelsens f6rfattningssamling 1982: 20, Stockholm.

Grandjean, E. 1981, Fitting the task to the man. An ergonomic approach. Taylor & Francis Ltd, Basingstoke.

K-konsuR. 1974, StorM5kspersonalens arbetsmilj& Del I och De1 II. ASF-project 74/114, Stockholm.

Salonen, A., and Heinsalmi, P. 1979, OWAS Ty6asentojen havainnointij~'rjestelm~, SITRA, Sarja B, No 50, Helsinki.

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