Kemiringan atap: sudut, persen dan kenaikan

Dari kenaikan vertikal dan jarak horizontal, hitung sudut, kemiringan persen, kemiringan atap (x per 12), panjang miring dan faktor kasau.

Diperbarui Contoh terverifikasi: 8

Negative for a downhill slope
Coba
Sudut
°
Sudut: 26.5651 °
Tempat desimal maksimum: 4; Terdekat, jika berjarak sama menjauhi nol
Nilai
50%
Roof pitch
6in 12
Ratio (rise : run)
1 : 2
Rise per unit of run
0.5
Rafter length factor
1.118034
Slope length
13.4164cm

This slope rises 0.5 for every 1 of run: 26.57° from horizontal, a 50 % grade, or a 6/12 roof pitch. Its sloped length is 13.4164 cm.

Slope profile, to scale

run 12 cmrise 6 cm26.57°6/12 pitch · 50 %
Cara menghitung S
  1. Slope

    m=riserun=612=0.5m = \frac{\text{rise}}{\text{run}} = \frac{6}{12} = 0.5
  2. Sudut

    θ=arctan⁡m=arctan⁡0.5=26.565051∘\theta = \arctan m = \arctan 0.5 = 26.565051^\circ
  3. Grade and pitch

    grade=100m=50 %,pitch=12m=6 in 12\text{grade} = 100m = 50\,\%,\qquad \text{pitch} = 12m = 6 \text{ in } 12
  4. Rafter factor

    1+m2=1+0.52=1.118034\sqrt{1 + m^2} = \sqrt{1 + 0.5^2} = 1.118034

    Multiply a horizontal run by this to get the sloped length.

  5. Slope length

    rise2+run2=12×1.118034=13.416408 cm\sqrt{\text{rise}^2 + \text{run}^2} = 12 \times 1.118034 = 13.416408\,\text{cm}

Tentang Kemiringan atap: sudut, persen dan kenaikan

Every way of stating a slope comes from one ratio, m = rise ÷ run. The angle from horizontal is arctan m, the percent grade is 100m, the roof pitch is 12m (units of rise per 12 of run), and the rafter factor √(1 + m²) turns a horizontal run into the sloped length. Enter a rise and run, or any one of the other forms, and the rest follow.

The default rise of 6 over a run of 12 is a 6/12 roof: 26.57°, a 50% grade and a rafter factor of 1.1180, so 12 cm of run needs 13.4164 cm of rafter. Ramps and roads use the same numbers: the steepest ramp the 2010 ADA Standards allow, 1:12, is an 8.33% grade, or 4.76°.

Percent grade is not an angle: a 100% grade is 45°, and a vertical face has no finite grade or pitch, so angles must lie between −90° and 90°. A negative rise describes a downhill slope.

Contoh penyelesaian

Rise 6, run 12 (a 6/12 roof)

Ukuran yang diketahui
Rise and run
Rise
6 cm
Run (horizontal distance)
12 cm
Satuan hasil
Sentimeter (cm)
Sudut
26.565051 °
Nilai
50%
Roof pitch
6 in 12
Ratio (rise : run)
1 : 2
Rafter length factor
1.118034
Slope length
13.416408 cm

Sumber pemeriksaan: Python 3.8 math: degrees(atan(0.5)), sqrt(1.25), sqrt(6**2 + 12**2)

45°

Ukuran yang diketahui
Sudut
Angle from horizontal
45 °
Nilai
100%
Roof pitch
12 in 12
Ratio (rise : run)
1 : 1
Rafter length factor
1.414214

Sumber pemeriksaan: tan 45° = 1; Python 3.8 math.sqrt(2)

8 % road grade

Ukuran yang diketahui
Percent grade
Nilai
8%
Sudut
4.573921 °
Roof pitch
0.96 in 12
Ratio (rise : run)
1 : 12.5

Sumber pemeriksaan: Python 3.8 math: degrees(atan(0.08)); 12 × 0.08; 1/0.08

4/12 roof pitch

Ukuran yang diketahui
Roof pitch
Pitch
4 in 12
Sudut
18.434949 °
Nilai
33.333333%
Rafter length factor
1.054093

Sumber pemeriksaan: Python 3.8 math: degrees(atan(4/12)), sqrt(1 + 1/9)

Pertanyaan

How do you convert percent grade to degrees?

Take the arctangent of the grade divided by 100: θ = arctan(grade/100). An 8% road grade is arctan 0.08 = 4.57°, and a 100% grade is 45°, not 90°. The reverse is grade = 100 × tan θ, so a 30° slope is a 57.7% grade.

What angle is a 6/12 roof pitch?

26.57°. A pitch of x/12 means x units of rise for every 12 of run, so the angle is arctan(x/12): 4/12 is 18.43°, 6/12 is 26.57°, 8/12 is 33.69° and 12/12 is 45°. The rafter factor for 6/12 is √1.25 = 1.118, so 12 ft of horizontal run needs 13.42 ft of rafter before any overhang.

What is the maximum slope for a wheelchair ramp?

1:12 under the 2010 ADA Standards for Accessible Design (§405.2): one unit of rise for every 12 of run, an 8.33% grade or 4.76°. Each ramp run may rise at most 30 in (§405.6), so a 30 in rise needs a run of at least 30 ft. Other countries set their own limits in their building codes.

How do you calculate rise over run?

Divide the vertical rise by the horizontal run, both in the same unit: m = rise/run. A roof that rises 6 in over 12 in of run has m = 0.5. Measure the run horizontally, not along the surface: the sloped length here is 13.42 in, and dividing by it gives 0.447, the sine of the angle rather than the slope.

Seberapa akurat “Kemiringan atap: sudut, persen dan kenaikan”?

Akurasi bergantung pada masukan dan asumsi metode. Aritmetika desimal memakai 50 digit signifikan, tetapi perkiraan, metode numerik dan data sumber bisa kurang presisi; pembulatan yang ditampilkan tidak menghilangkan batasan itu. Contoh penyelesaian yang diperiksa dengan sumber independen: 8. Misalnya, “Rise 6, run 12 (a 6/12 roof)” diperiksa dengan Python 3.8 math: degrees(atan(0.5)), sqrt(1.25), sqrt(6**2 + 12**2).

Dari mana metode ini berasal?

OpenStax College Algebra 2e, §4.1 — slope as rise over run; US Access Board, ADA Standards §405.2 — ramp slope 1:12 (8.33 %).

Tentang kalkulator ini

m=riserun,θ=arctan⁡m,grade=100m %pitch=12m in 12,factor=1+m2\begin{gathered} m = \frac{\text{rise}}{\text{run}},\quad \theta = \arctan m,\quad \text{grade} = 100m\,\% \\[6pt] \text{pitch} = 12m \text{ in } 12,\quad \text{factor} = \sqrt{1 + m^2} \end{gathered}

Sumber

  1. OpenStax College Algebra 2e, §4.1 — slope as rise over run
  2. US Access Board, ADA Standards §405.2 — ramp slope 1:12 (8.33 %)

Diperiksa dengan referensi

Kalkulator ini mencakup 8 contoh perhitungan dengan jawaban dari sumber independen. Contoh tersebut dijalankan dalam rangkaian pengujian dan dapat Anda jalankan di sini juga.

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