Seat Dimensions Research Articles

Child seat belt guidelines: Examining the 4 feet 9 inches rule as the standard.

Current American Academy of Pediatrics recommendations regarding transition from child safety/booster seat to adult safety belt use indicate that children should be at least 4 feet 9 inches, 8 years old, or 80 pounds. Proper fit in the vehicle seat, assessed with a five-point fit test, should also be met. Although most children reach 4 feet 9 inches around age 8 years, each child and vehicle presents a unique combination; thus a child may not fit appropriately in all vehicle types using only the 4 feet 9 inches requirement. We enrolled children, aged 7 years to 12 years, into our study. Height, weight, and demographic data were obtained. A Child Passenger Safety Technician then performed the five-point fit test in each of a uniform lineup of five vehicles. Data were collected on fit in the standard vehicle seat and also in a booster seat. We set 90% as the threshold proportion of children who meet all criteria for proper fit to validate current recommendations of a height of 4 feet 9 inches. Data were collected on 388 children. The percentage of 90% proper fit was met in the compact car and small sport-utility vehicle (SUV). However, only 80 (77%) of 104 students (p < 0.0001) that were 4 feet 9 inches or higher fit properly in the large SUV, only 87 (83%) of 105 students (p = 0.02) fit properly in the pickup truck, and only 91 (89%) of 102 students (p = 0.74) fit properly in the minivan. Substantial proportions of children meeting current height guidelines for an adult seat belt do not meet safety requirements for fit, especially in larger, commonly used vehicles (large SUVs and trucks). This emphasizes the need for evaluation of fit by a trained personnel and/or development of standard back seat dimensions in all vehicles for maximum safety. Epidemiologic level 1.

Ergonomics assessment of locally fabricated passenger seats in trotro vehicles in Accra, Ghana

Abstract Trotro vehicles constitute one of the major means of transportation in Ghana by way of ferrying people and goods. Most trotros are originally brought into the country as load carrying vehicles, which are then converted into passenger vehicles. Locally designed seats are then fabricated and secured into the vehicles. The study explored the ergonomic evaluation of the locally fabricated passenger seats with anthropometric measures of passengers and also compared the seat dimensions to required standards. The study was undertaken at seven selected bus stations in Accra, the capital city of Ghana. The study composed of 307 volunteer passengers comprising 175 females and 132 males with ages spanning from 18 to 60 years. The dimensions of ninety locally fabricated seats were collected from ninety randomly selected trotro vehicles. Ergonomic assessment was performed to determine match or mismatch between the anthropometric measures and vehicle seating dimensions. In addition, the fabricated seat dimensions were compared to both local and international vehicle seat standards. High mismatches indicating that the passenger seats were probably too deep or too high were observed for seat height – popliteal height, seat depth – buttock popliteal length, and seat breadth – hip breadth. A low mismatch was observed between the sitting height and backrest height for 99.4% of participants. Only four and ten out of the ninety seats complied with specified standard seat length and backrest to backrest distance, respectively. The high prevalence of mismatch is a possible indication that most locally fabricated seats do not adequately accommodate majority of passengers. Furthermore, it appears that anthropometric measures and standard vehicle seat dimensions are not considered during seat design, with potential health ramifications pertaining to the safety, comfort and sitting posture of passengers.

Ergonomic design of a Bangladesh bus passenger seat

BACKGROUND: Passenger seats need to be designed according to ergonomic guidelines for long hour sitting travel. In Bangladesh, passenger seats are designed and fabricated by the local manufacturers who have no knowledge about anthropometry. As a result, passenger has to face stress, fatigue, headac he and other disorders. OBJECTIVE: To compare passengers' anthropometric measurements and relevant existing seat dimensions for identifying possible discrepancy and recommending an optimum design. METHODS: In this study the passengers' anthropometric measurements and relevant existing seat dimensions were compared to identify possible discrepancy. RESULTS: The result represented a considerable mismatch between body dimensions of passengers and the existing seat dimensions. The recommended new seat dimensions would enhance match percentage. CONCLUSIONS: The design and allocation of passenger seats were given on the basis of passenger's anthropometry. The proposed seat dimensions would ensure a safe and comfortable journey for the passengers.

Health risk, price efficiency, and airline seat size regulation

Purpose: Airline cost-cutting measures have led to shrinking economy-class seats ever since deregulation went into effect 35 years ago. Deep vein thrombosis and pulmonary embolism, along with restricted mobility, particularly during an emergency evacuation, are among the health and safety hazards seat shrinkage has created for passengers. These have led to several regulatory attempts to define and standardize minimum aircraft seat dimensions. The question for scholarly investigation is whether government can efficiently regulate how air travelers value their health, safety, and comfort (and what consequences might arise therefrom).Methods: Aircraft seat regulation is modeled as a Stag Hunt with two sets of utility-maximizing and interactive players: passengers and airlines. The strategic choices available to each one are identified and tested in the context of a single-play game.Main findings: We find two likely outcomes of passenger and airline risk calculations and mitigation strategies against a set of alternatives and their expected consequences. The tension between the payoff-dominant and risk-dominant equilibria arises when players rationally pursue either strategy, depending on what they expect the other will do. Despite the lower payoffs to either player, we predict that the second-best and risk-dominant strategy will result from players' risk calculations. Successful lobbying against airline seat regulation derives not so much from the vast resources and efforts committed to it, but from the demonstrable power of market forces to sustain it.Conclusion/value: Absent any optimal strategy to address corresponding price increases, regulatory efficacy will depend on the risk propensities of market forces. Aircraft seat pricing reflects consumer supply and demand information pertaining to it. Any information changes will be instantly reflected in the market price of aircraft seats. Game simulation thus offers empirically verifiable predictions about choices that affect the control of scarce resources, particularly when passengers and airlines compete over them under conditions of risk and uncertainty.

An ergonomic assessment of operating table and surgical stool heights for seated otolaryngology procedures.

Background:Musculoskeletal injuries, such as neck and back pain, during a surgeon's career are common. However, studies on ergonomics are limited with regard to seated otolaryngologic procedures. Key elements of an ergonomic operating environment include the height of operating tables and surgical chairs. Surgeons benefit from proper support and positioning to prevent musculoskeletal injuries and reduce occupational risk.Objective:The purpose of this study was to evaluate operating table and surgical seat heights, and determine whether adjustments can be made for various surgeon physiques.Methods:Operating tables and surgical seat dimensions were measured at local hospitals, and the information was complemented by an online search of other models.Results:Five unique operating tables and five unique surgical stools were identified, both in the local hospital and in a search on the Internet. Of available tables, the greatest range was 63.5–124.5 cm, which reaches above the maximum suggested working height of 76.2 cm. The surgical stool with the widest range was adjustable from heights of 50.8–72.4 cm. This combination of operative table and surgical stool provided the greatest range of heights.Conclusion:Of the available tables and stools measured, the combination of surgical table with a range of 63.5–125.7 cm and surgical stool with a range of 50.8–72.4 cm provided the greatest versatility for diverse physician heights. In ergonomic terms, this combination may reduce physical fatigue and create a potentially safer working environment for seated surgeons.

Incorporating Malaysian's Population Anthropometry Data in the Design of an Ergonomic Driver's Seat

An ergonomically designed driver's seat is crucial in ensuring quality, comfort and safe driving. The increase in road accidents every year is mostly linked to drivers’ fatigue. Therefore, posture comfort is an important aspect in driver's seat design. The aim of this study is to design a driver's seat which is suitable for Malaysians. There are three main objectives in this study; firstly, to investigates the comfort level and safety system of the existing driver's seat, secondly, to identify and determine parameters which may affect comfort and the driver's seat safety system, and lastly, to develop and design an ergonomic driver's seat. Anthropometric data of drivers should be used during the driver's seat design stage. Critical dimensions of the driver's seat and anthropometric data must be taken into consideration in order to optimize the comfort level and safety of the seat. Previous studies showed that the evaluation of driver's seat discomfort should include both objective and subjective evaluations. The seat discomfort will negatively affect the driver's performance. All information pertaining to the driver's seat design was obtained through research on the related subjects. In the data collection phase, the objective evaluation method was used in determining the seat's dimension while subjective evaluation was used to gather information on the drivers’ experience. Anthropometric data from 1405 male and female subjects were collected and stored in a database. Meanwhile, subjective evaluation on driver's seat discomfort was conducted on 100 male and female respondents. The SPSS software was used to analyse the data. Every parameter that affects the safety and comfort of the driver's seat were then used to design a new driver's seat. The parameters that were taken into account are backrest height, cushion width, cushion length and adjustability. These parameters were then matched with the Malaysian drivers’ anthropometric data. Finally, the dimensions of the new driver's seat were determined: 520mm cushion width; 380mm cushion length, 480mm backrest width, 407.5mm backrest height and 180mm adjustability.

Design of combine harvester seat based on anthropometric data of Iranian operators

Harvesting operation with agricultural combines imposes excessive physical loads on the operators and the poorly designed seats may be an important contributory factor in this regard. This aims of this field study were to evaluate the possible mismatch between seat dimensions of existing harvesting combines and anthropometric characteristics of 200 Iranian operators and to propose seat dimensions based on anthropometric principles. The anthropometric dimensions of each individual operator were compared to the relative seat dimensions using the equations proposed in the literature. The results showed a considerable mismatch for different seat dimensions including upper backrest width (100%), seat height (97%), armrest height (83.7%), seat width (52.8%), lower backrest width (40.6%) and seat depth (39.5%). This meant that the existing combine seats were too high, too narrow and too shallow and had armrests and backrests which did not match with body dimensions of the majority of the operators. It was shown that compared to the existing designs, the new proposed dimensions (including seat height = 400 mm, seat width = 450 mm, seat depth = 410 mm, armrest height = 290 mm, backrest height = 420 mm, upper backrest width = 360 mm and lower backrest width = 400 mm) better matched to the operator's anthropometry, with the match percentages ranging from 77% to 100%. Relevance to industryThe design and manufacturing of agricultural machinery should be made based on the anthropometric characteristics of actual users to avoid unnecessary demands on them. This study provide additional data on the operator's anthropometry that can be used as a starting point for designing more appropriate agricultural machinery or used by other researchers in the field.

Development of aspect dummy considering seat dimension factor

The HPM-I dummy that was used to design car seats was developed by referring to human body dimension data in the 1960s, not to reflect changes of body sizes in accordance with time flow. Also, the HPM-I dummy that was made of one plate of a back rest could not express various kinds of postures. Thereafter, HPM-II, which had three back rests, was developed, but it could not consider various kinds of seat dimension factors by body size of 50th percentile male. We developed not only a 5th percentile female model but also 95th percentile male model to make use of them for automobile seat design and rating. The study developed the HARB model, HPM-II model, and CAD model of each percentile based on 50th percentile male HPM-II dummy.

Manikin families representing obese airline passengers in the US.

Aircraft passenger spaces designed without proper anthropometric analyses can create serious problems for obese passengers, including: possible denial of boarding, excessive body pressures and contact stresses, postural fixity and related health hazards, and increased risks of emergency evacuation failure. In order to help address the obese passenger's accommodation issues, this study developed male and female manikin families that represent obese US airline passengers. Anthropometric data of obese individuals obtained from the CAESAR anthropometric database were analyzed through PCA-based factor analyses. For each gender, a 99% enclosure cuboid was constructed, and a small set of manikins was defined on the basis of each enclosure cuboid. Digital human models (articulated human figures) representing the manikins were created using a human CAD software program. The manikin families were utilized to develop design recommendations for selected aircraft seat dimensions. The manikin families presented in this study would greatly facilitate anthropometrically accommodating large airline passengers.

The anthropometric match between high school learners of the Cape Metropole area, Western Cape, South Africa and their computer workstation at school

Study designDescriptive study. ObjectiveThe objective of this study was to present anthropometric data from high school students in Cape Metropole area, Western Cape, South Africa that are relevant for chair design and whether the dimensions of computer laboratory chairs currently used in high schools match linear anthropometrics of high-school students. Summary of Background Data. Learner–chair mismatch is proposed as a cause of poor postural alignment and spinal pain in adolescents. A learner–chair mismatch is defined as the incompatibility between the dimensions of a chair and the anthropometric dimensions of the learner. Currently, there is no published research to ascertain whether the furniture dimensions in school computer laboratories match the anthropometrics of the students. This may contribute to the high prevalence of adolescent spinal pain. MethodsThe sample consisted of 689 learners, 13–18 years old. The following body dimensions were measured: stature, popliteal height, buttock-to-popliteal length and hip width. These measurements were matched with the corresponding chair seat dimensions: height, depth and width. Popliteal and seat height mismatch was defined when the seat height is either >95% or <88% of the popliteal height. Buttock–popliteal length and seat depth mismatch was defined when the seat depth is either >95% or <80% of the buttock–popliteal length. Seat width mismatch is defined where the seat width should be at least 10% and at the most 30% larger than hip width. ResultsAn 89% of learners did not match the seat. Five percent of learners matched the chair depth, the majority was found to be too big. In contrast, 65% of the learners matched the chair width dimension. ConclusionsA substantial mismatch was found. The school chairs failed standard ergonomics recommendations for the design of furniture to fit the user. This study supports the conclusion that there is no one-size-fits-all solution. There is an urgent need for chairs that are of different sizes or that are adjustable.

OPTIMISING SEAT LENGTH DESIGN TO MINIMISE EXTRA PASSENGERS ON ALL-TERRAIN VEHICLES

BackgroundThe presence of extra riders increases the likelihood of an all-terrain vehicle (ATV) crash and injury. However, many ATVs have seats long enough to accommodate passengers.Aims/Objectives/PurposeTo determine if ATV seats...

Review of anthropometric considerations for tractor seat design

Tractor driving imposes a lot of physical and mental stress upon the operator. If the operator's seat is not comfortable, his work performance may be poor and there is also a possibility of accidents. The optimal design of tractor seat may be achieved by integrating anthropometric data with other technical features of the design. This paper reviews the existing information on the tractor seat design that considers anthropometry and biomechanical factors and gives an approach for seat design based on anthropometric data. The anthropometric dimensions, i.e. popliteal height sitting (5th percentile), hip breadth sitting (95th percentile), buttock popliteal length (5th percentile), interscye breadth (5th and 95th percentile) and sitting acromion height (5th percentile) of agricultural workers need to be taken into consideration for design of seat height, seat pan width, seat pan length, seat backrest width and seat backrest height, respectively, of a tractor. The seat dimensions recommended for tractor operator's comfort based on anthropometric data of 5434 Indian male agricultural workers were as follows: seat height of 380 mm, seat pan width of 420–450 mm, seat backrest width of 380–400 mm (bottom) and 270–290 mm (top), seat pan length of 370±10 mm, seat pan tilt of 5–7° backward and seat backrest height of 350 mm. Relevance to industry The approach presented in this paper for tractor seat design based on anthropometric considerations will help the tractor seat designers to develop and introduce seats suiting to the requirements of the user population. This will not only enhance the comfort of the tractor operators but may also help to reduce the occupational health problems of tractor operators.

Development of a New Geometric Bicycle Saddle for the Maintenance of Genital–Perineal Vascular Perfusion

To identify a bicycle saddle model for cyclists who cover long distances, to minimally reduce the compression on the structures of the pelvic floor, thereby protecting blood perfusion of the penis and avoiding possible consequences on penile erection. A comparison between a new geometric development of a bicycle saddle model (SMP) and one of the more frequently used models by professional cyclists was made. The measurement of the partial pressure of penile transcutaneous oxygen (PtcO(2)) in 29 healthy voluntary cyclists was recorded to investigate the differences of compression from two different saddles on the vascular structures of the perineum. The PtcO(2) was recorded at 3 and 10 minutes in conditions of static sitting. Then, the values of PtcO(2) were recorded for 15 minutes while the cyclists were in a 60-degree position and in stable hemodynamic conditions. A t-test was performed to measure the level of confidence. The clear superiority of the SMP saddle in preventing vascular compression of the perineal structures was demonstrated to be statistically significant. The experiment validated the effectiveness of the SMP saddle in limiting the compression on the pelvic floor. In addition, the SMP saddle introduces compatible seat dimensions that cyclists prefer to cover long distances.

Exploring the Optimum Train Seat Dimensions for Passengers' Comfort Postures

The purpose of this paper is to investigate the train seat dimensions suitable for keeping comfortable postures. We designed a special experimental seat of which the lengths and angles are adjustable separately. Seat dimensions keeping subjects comfortable were measured for the restricted posture and the extended posture. The differences of dimensions for the two postures and the body sizes of subjects were statistically analyzed. The correlation coefficients between seat dimensions and subjects' heights and weight were also calculated.

Subjective assessment of fork-lift truck seats under laboratory conditions

A subjective assessment of fork-lift truck seats has been carried out to assess the range of preferred seat dimensions and the acceptability of different seat adjustments to fork-lift truck drivers. Twelve fork-lift truck seats fitted to a fixed bench were assessed by twelve fork-lift truck drivers. For each seat, each driver completed a questionnaire that covered the following areas: eleven seat dimensions, four seat adjustments and other features (arm rests, safety belts and safety wings). The drivers assessed the dimensions of a seat chosen at random, before moving to the adjacent seat in either a clockwise or anticlockwise direction. Before each assessment, they were asked to look forward and backward in the seat as though they were driving a fork-lift truck. In general, significant correlations were obtained between the subjective assessments and objective measurements of the seat dimensions. This enabled preferred seat dimension ranges to be defined. Fork-lift truck drivers ranked the forward–backward and the backrest inclination adjustments as most important. The results showed that although the drivers had previous experience in the use of suspension seats, they did not understand the purpose of the weight adjustment. All adjustments should be easy to find, accessible, easy to move and they should enable a range of adjustments. In addition, clear and simple information on the seat is needed, especially for the weight adjustment. The most recently designed seats generally had dimensions within the preferred ranges compared with the older generation seats, mainly because they had more adjustments. However, the results show that adjustments on fork-lift truck seats could be improved further. Some tentative conclusions are made for the preferred fork-lift truck seat dimensions and adjustment ranges which are based on the evidence from this restricted sample of fork-lift truck drivers. They may be useful for seat and truck designers in the preparation of a standard on fork-lift truck seat dimensions.