Factors affecting the usability of stairs

1. Factors affecting the usability of stairs Dr Michael Wright 21st October 2002

2. Contents of presentation • Current UK regulations • Our research • Our results and recommendations

3. What are the current UK requirements for stairs? • There are two Building Regulations which cover stair design • Part K: Stairs, ramps and guards • Part M: Access and facilities for disabled people

4. Approved Document KInstitutional and assembly stairs • Maximum rise = 180 mm • Minimum going = 280 mm • 550 mm £ 2Rise + Going £ 700 mm • Minimum Headroom = 2 m For maximum rise for stairs providing the means of access for disabled people reference should be made to Approved Document M

5. Going plus twice rise = 700 mm Going plus twice rise = 550 mm 240 220 200 180 Rise (mm) 160 140 120 100 80 180 200 220 240 260 280 300 320 340 360 380 400 Going (mm)

6. Approved Document KInstitutional and assembly stairs - continued • No minimum width recommended • Maximum length of flight is 16 risers • Level landings at top and bottom of every flight (at least as long as the narrowest part of the flight) • Stairs narrower than 1 m should have at least 1 handrail, otherwise a handrail on both sides (mounted between 900 mm and 1000 mm from pitch line)

7. Approved Document KInstitutional and assembly stairs - continued • Flights and landings should be guarded at the sides if there are two or more risers • If children under 5 years might use the stair the guarding should not be readily climbable, nor should a 100 mm sphere be able to pass through the guarding. • The height of the guarding should be at least 900 mm.

8. What can be done to make stairs easier to use? The regulations in Part K were drawn up with an “average” user in mind. Part M deal with “disabled people” which means, according to the regulations, someone who has “(a) an impairment which limits their ability to walk or which requires them to use a wheelchair for mobility, or (b) impaired hearing or sight.”

9. Approved Document MExternalNon-Dwelling Stairs - disabled people • Top landing has corduroy tactile surface, 400 mm from top nosing to 1200 mm from top nosing • Nosings distinguishable through contrasting brightness • Unobstructed widths of at least 1 m • Rise between landings a maximum of 1.2 m • Maximum rise = 150 mm • Minimum going = 280 mm

10. 240 220 200 180 Rise (mm) 160 140 120 100 80 180 200 220 240 260 280 300 320 340 360 380 400 Going (mm)

11. Approved Document MExternalNon-Dwelling Stairs - continued • Risers are not open • A flight of 2 or more risers should have a suitable continuous handrail on both sides • Handrail is at least 900 mm above the pitch line • Each handrail should extend at least 300 mm beyond the first and last nosing • Profile of handrail is suitable (shows a circular one, 45 mm to 50 mm diameter)

12. Approved Document MInternalNon-Dwelling Stairs - disabled people • No requirement for provision of tactile surface • Nosings distinguishable through contrasting brightness • Unobstructed widths of at least 1 m • Rise between landings a maximum of 1.8 m • Maximum rise = 170 mm • Minimum going = 250 mm Less generous due to more onerous design constraints

13. 240 220 200 180 Rise (mm) 160 140 120 100 80 180 200 220 240 260 280 300 320 340 360 380 400 Going (mm)

14. Approved Document MInternalNon-Dwelling Stairs - continued • Risers are not open • Same requirements for suitable handrail Exceptionally the provisions of the rise of a flight may be varied if particular storey heights or the need to gain access beneath an intermediate landing dictate, or the additional length of the stair has unreasonable effects on usable floor areas. Then use AD K

15. So, what is there left to do? Some groups have not had their needs addressed, and there are other features which are not dealt with in the Approved Documents, for example not all of the following groups are explicitly considered; • less able stair users: • elderly (over 75 years of age), • ambulant disabled, • visually impaired, • elderly visually impaired (over 70 years of age); • people of extreme sizes: • tall people (above 95th percentile for height), • heavy adults (above 95th percentile for weight), • small adults (below 5th percentile for height), • children.

16. What was done? These groups were presented with 5 different stairs, they used them, and in focus groups we collected their opinions on every design feature they had experienced. These were compared with “average” subjects, those who fall within 15% of the mean weight and height of the adult population in the UK, one male group and one female group. This work was funded by the Office of the Deputy Prime Minister

17. Pitch Headroom Rise Going Dimensions

18. Going • Is perhaps the most influential of all stair dimensions • Previous research has shown that larger goings are preferred

19. Subjective questions • I would feel safe having this stair in my home • I had to pull myself up the stair using the handrail • I hardly had to look at the steps as I came down the stair • There was enough room to put my feet comfortably on each step • I relied on the handrail to support me as I came down the stair • I felt safe walking up the stair • I would not like to negotiate this stair in the dark • I had to turn my feet sideways to place them on each step • I had to concentrate all the time when climbing down the stair • I could hurry / rush down the stair if I had to • While descending I had to walk with my body twisted • I felt that there was not enough room for my feet • It would have been easy to fall down the stair • Its easy to mis-judge a step when climbing down • I felt safe walking down the stair

20. 700 0 Left Axis 600 100 Q2 mean rank Q5 mean rank Q7 mean rank Q8 mean rank 500 200 Q9 mean rank Q11 mean rank Q12 mean rank Mean Rank Mean Rank 400 300 Q13 mean rank Q14 mean rank Right Axis Q1 mean rank 300 400 Q3 mean rank 200 500 100 600 150 175 200 225 250 275 300 325 350 375 400 425 Going (mm) Subjective responses Q15: I felt safe walking down the stair Q4 mean rank Q6 mean rank Q10 mean rank Q15 mean rank

21. No difference in opinions from 275 mm onwards Subjective responses 700 0 Left Axis 600 100 Q2 mean rank Q5 mean rank Q7 mean rank Q8 mean rank 500 200 Q9 mean rank Q11 mean rank Q12 mean rank Mean Rank Mean Rank 400 300 Q13 mean rank Q14 mean rank Right Axis Q1 mean rank 300 400 Q3 mean rank Q4 mean rank Q6 mean rank Q10 mean rank 200 500 Q15 mean rank 100 600 150 175 200 225 250 275 300 325 350 375 400 425 Going (mm)

22. Proportion of shoe overhang 60% 50% 40% 30% Percentage of shoe length 90th Percentile 20% 10% 10th Percentile 0% 150 175 200 225 250 275 300 325 350 375 400 425 Going (mm)

23. Going • Is perhaps the most influential of all stair dimensions • Previous research has shown that larger goings are preferred • This preference was confirmed within this study

24. What goings were preferred? 298 mm 250 mm 220 mm 300 mm 250 mm ü ü

25. Going • Users found it difficult to consider going in isolation

26. What about rise and going combinations? 298 mm going 250 mm 220 mm 300 mm 250 mm x ? ü x ü rise 222 mm 185 mm 186 mm 200 mm 163 mm

27. 240 220 200 180 Rise (mm) 160 140 120 100 80 180 200 220 240 260 280 300 320 340 360 380 400 Going (mm)

28. Headroom 1948 mm down stand 2167 mm parallel x ?

29. Conclusions • Larger goings are preferred, no smaller than 250 mm • Going cannot be considered in isolation • A rise of 200 mm is acceptable with the right going • May need to limit pitch to about 37° • Tall users are used to restricted headroom at 2000 mm • Parallel soffits can feel claustrophobic if they extend too far along the flight.

30. Handrails

31. Purpose of handrails • Guidance • This is especially true for people who are visually impaired, who tend to use the handrail as a guide • Support • This is especially true for people who have difficulty walking, or are old, who can use the handrail to keep balanced or to pull themselves up when climbing • Stability • In the event of a fall or a wobble, a handrail can help stabilise the user and may help prevent a serious injury

32. Areas to be covered • Shape • Size • Continuity and gap • Overhang • Height • Number

33. Shape - pigs ear x

34. Shape - traditional ?

35. ü ü ü Shape - circular, oval, flat

36. 50 Size 50 mm diameter • Beyond 95th percentile grip 46 mm • Difficult to get thumb around

37. 30 Size 30 mm diameter • Beyond 5th percentile grip 32 mm • Cannot get fingers past supports

38. Size • 5th to 95th percentile grip for UK adult population 32 30 46 50 x x

39. Size - circular, oval, flat • May be better consider perimeter for other acceptable shapes • Perimeter should be between 100 mm and 150 mm

40. Continuity and gap • 50 mm too small (50 mm to 60 mm recommended in BS8300) • 100 mm too large • 75 mm preferred • Should continue throughout flight

41. Overhang At the top • Indicates start of flight in descent • Used to pull user up last step • Should be at least 300 mm At the bottom • Indicates end of flight in descent • Less necessary than at top • Could use alternative termination • Clothes might catch on open ends

42. Height • 900 mm - 1000 mm preferred • Children choose higher handrail

43. Number • Two handrails preferred • Provide choice in descent • 800 mm to 1000 mm apart • Some felt unsafe with no handrails • Some need handrail to climb

44. Conclusions • Two handrails • 800 mm - 1000 mm apart • 900 mm above pitch line • Handrails should extend beyond flight, especially at the top • 75 mm wall gap • Diameter between 32 mm and 46 mm or • Perimeter between 100 mm and 150 mm • Circular oval, and flat shapes work best

45. Other design features • Landings (for resting) • Winders • Open risers • Overhanging nosings • Hard Surfaces • Designation • Contrasting nosings

46. Landings • Visually impaired users did not like the landings, since the hardest part of the stair to negotiate was the transition to or from the level and this had to be performed more than once with a landing.

47. Landings • Landings dictate where a rest can occur • The height of the landing did not seem to be an issue • When comparing the same overall length of stair, a larger going of 300 mm was preferred over a 900 mm landing in the flight

48. Winders • Difficult to maintain constant going between steps, which may lead to confusion • Difficult for most people to negotiate, especially those with poor vision

49. Open and partial risers, overhanging nosings • Open risers disliked by many users, impossible for some users • Traditional nosings can be just as bad Full x x x Full Full Open Partial

50. x x x Hard surfaces • Hard surfaces make noises, which is disconcerting for some users • Can cause more serious injuries on collisions Carpet Linoleum Wood Metal Tile