RAMP | STAIRCASE | LADDER

            HAVE YOU EVER GOT THIS COMMENTS THAT YOU HAVE DESIGN A WRONG STAIRCASE? OR DO YOU HAVE ANY CONFUSION IN DESIGNING THE STAIRCASE? WELL THAN THIS POST IS FOR YOU.

            RAMP, STAIRCASE  LADDER THIS THREE AREA DESIGN SINCE THE HUMAN RACE HAS to BUILD ITS FIRST HOME. THE ALL 3 ELEMENT IS DESIGN TO MAKE VERTICAL TRANSPORTATION MORE COMFORTABLE FOR US. BUT NOBODY DOES EVER SEE THEM ONE IN TERMS OF CALCULATION. HERE I AM GOING TO EXPLAIN ABOUT THESE 3 VERTICAL TRANSPORTATION DESIGN ELEMENT HOW TO CALCULATE IT.

            THESE ALL 3 THERE ELEMENT HAS ONE BASIC COMMON THING IN IT IN TERM OF CALCULATION. THAT IS LINE OF GOING. AS ANGLE OF LINE OF GOING START TO RAISE BECOMES RAMP TO STAIRCASE TO LADDER.

 

There are 3 CATEGORIES IN EACH ELEMENT IN TERMS OF COMFORT IN USING IT. STEEP, COMFORTABLE & LOOSE. AS YOU CAN UNDERSTAND FROM WORD ITSELF. BUT WHAT IS EXACT MATH IN THIS 3 TERM AS IT DEPENDS ON COMPLETELY END USER, WHICH IS GOING TO BE ANYONE, FROM A CHILD TO A SENIOR CITIZEN, FROM WORKER TO A PREGNANT WOMAN, ALL THE USER COMES WITH DIFFERENT ANTHROPOMETRY. HOW CAN YOU JUSTIFY ALL? WELL, YOU CAN’T! 
SO, THE DESIGNERS HAVE TAKEN AN AVERAGE HUMAN BODY MEASUREMENTS & DESIGN ACCORDING THAT SO EVERYONE CAN GET MAXIMUM POSSIBLE COMFORT LEVEL IN SINGLE DESIGN. LET’S JUST NOT DIVE into THAT  START UNDERSTANDING JUST MATH!

WE AS A HUMAN CAN LIFT OUR LEG COMFORTABLY IN WALKING CONDITION IS 100 MM TO 110 MM, WHILE CLIMBING ON A STAIRCASE IT IS 135 MM TO 170 MM, WHILE ON LADDER IS 300 MM TO 380 MM.  AN AVERAGE ADULT HUMAN FOOT IS AROUND 230 MM TO 250 MM LONG. ALL CALCULATION IS AROUND THIS MEASUREMENT. LET’S START UNDERSTANDING HOW IT HELP US IN DESIGN THESE 3 VERTICAL TRANSPORTATION DESIGN ELEMENTS.

FOR RAMP THE ANGLE FOR LINE OF GOING IS 3.5° TO 9.0° IS COMFORTABLE. NOW HOW TO DESIGN IT. WELL LET’S UNDERSTAND IN THIS WAY, YOU HAVE TO CLIMB 1 METER VERTICALLY (RISE) FOR THAT YOU HAVE TO TRAVEL 10 METERS HORIZONTALLY (RUN). THIS WILL BECAME YOUR RATIO FOR RAMP IS 1:10 SLOPE.

THERE IS SOME CALCULATION TO DERIVE ANGLE,

 ► TAN θ = 1/10

 ► θ = TAN^-1 (1/10)

 ► θ = 5.71° (3.5°9.0°)

SO, IT IS COMFORTABLE RAMP.

GENERALLY, RAMP HAVING RATIO 1:10 IS GLOBALLY ACCEPTED AS MOST COMFORTABLE RATIO. BUT AS PER SITE CONDITION USER REQUIREMENTS IT VARIES BETWEEN RATIO OF 1:16 TO 1:6.

            FROM 9.0° TO 26.0° IT IS CONSIDERABLE ANGLE FOR FLAT STAIRCASES, WHICH IS USED IN PUBLIC OPEN SPACES. IT IS CONSIDER AS LOOSE STAIRCASES AS IT HAS LOW RISERS HIGH RUN DIMENSION. FOR COMFORTABLE USE IT IS RECOMMENDED TO HAVE LINE OF GOING OF STAIRCASE IS BETWEEN 26.0° TO 33.0°.

NOW, HERE THE CALCULATION OF STAIRCASE ID BIT DIFFER FROM THE RAMP. WHERE IN THE RAMP WE CALCULATE ANGLE FROM RATIO OF ANGLE, HERE WE CALCULATE IT FROM RATIO OF LENGTH OF THE TREAD OR RUN TO HEIGHT OF THE RISER.

            FOR COMFORTABLE STAIRCASE CALCULATION IS

2 RISER + 1 TREAD = 600 MM TO 650 MM

BUT WAIT, HERE THE MO.ST OF US MAKES A MISTAKE WITH THIS CALCULATION WE HAVE TO ALSO CONSIDER HUMAN ANTHROPOMETRY. (I.E., LENGTH OF THE AVERAGE HUMAN FOOT ONE CAN COMFORTABLY PULL HIS LEG VERTICALLY)

SO, TAKING THAT IN MIND LETS TAKE TREAD OR RUN WIDTH 300 MM, SO WE GET

2 RISER = 600 – 300 (1 TREAD) = 300

1RISER = 150 MM

BOTH THE DIMENSION IS COMFORTABLE FOR HUMANS TO CLIMB THE STAIRCASE.

NOW THE ANGLE,

► TAN θ = 150/300

► θ = TAN^-1 (150/300)

► θ = 27° (26°<27°<33°)

SO, IT IS COMFORTABLE STAIRCASE.

FOR LINE OF GOING RAISE FROM 33° TO 41° IT WILL BECAME TOO STEEP FOR A STAIRCASE BUT SOMETIMES IT IS USED FOR LESS UTILISED ROOM SUCH AS LOFT OR ATTIC.

NOW, IT COMES FOR LADDER.

WHERE LENGTH OF THE SPACE IS TOO SHORT FOR THE STAIRCASE ON WILL GO WITH THE LADDER. IT IS NOT COMFORTABLE FOR CHILD OR OTHER PEOPLE WITH KNEE JOINT PROBLEM OR BACK PAIN PROBLEM. LADDER IS GENERALLY USED FOR MAINTENANCE WORK OR FOR EMERGENCY EXIT PLANS. IT SHOULD BE NEVER RECOMMENDED TO BE USE FOR HABITABLE ROOMS OR SPACES.

FROM 41° TO 75° STEPPED LADDER CAN BE USED IT IS IN BETWEEN DESIGN OF STAIRCASE & LADDER. FOR 75° TO 90° A FIXED LADDER OR ROPE LADDER IS FOR EMERGENCY PURPOSES.

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let's see what is the angle of your Staircase or Ramp or Ladder?
Rise =
Run =
Angle=