diff --git a/crates/python_api/docs/api/sfpe-handbook.rst b/crates/python_api/docs/api/sfpe-handbook.rst
index b44b787..8253ffd 100644
--- a/crates/python_api/docs/api/sfpe-handbook.rst
+++ b/crates/python_api/docs/api/sfpe-handbook.rst
@@ -108,6 +108,14 @@ Equation 50.16 - Flow Area Factor for Pressurization Systems
    :undoc-members:
    :show-inheritance:
 
+Equation 50.17 - Stairwell Temperature for Untreated Pressurization Air
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. automodule:: ofire.sfpe_handbook.chapter_50.equation_50_17
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
 Equation 50.18 - Fractional Effective Dose
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
diff --git a/crates/python_api/src/sfpe_handbook/chapter_50.rs b/crates/python_api/src/sfpe_handbook/chapter_50.rs
index 9d0a733..21d5959 100644
--- a/crates/python_api/src/sfpe_handbook/chapter_50.rs
+++ b/crates/python_api/src/sfpe_handbook/chapter_50.rs
@@ -2,6 +2,7 @@ pub mod equation_50_1;
 pub mod equation_50_14;
 pub mod equation_50_15;
 pub mod equation_50_16;
+pub mod equation_50_17;
 pub mod equation_50_18;
 pub mod equation_50_19;
 pub mod equation_50_2;
@@ -24,6 +25,7 @@ pub fn chapter_50(m: &Bound<'_, PyModule>) -> PyResult<()> {
     m.add_wrapped(wrap_pymodule!(equation_50_14::equation_50_14))?;
     m.add_wrapped(wrap_pymodule!(equation_50_15::equation_50_15))?;
     m.add_wrapped(wrap_pymodule!(equation_50_16::equation_50_16))?;
+    m.add_wrapped(wrap_pymodule!(equation_50_17::equation_50_17))?;
     m.add_wrapped(wrap_pymodule!(equation_50_18::equation_50_18))?;
     m.add_wrapped(wrap_pymodule!(equation_50_19::equation_50_19))?;
     m.add_wrapped(wrap_pymodule!(equation_50_20::equation_50_20))?;
diff --git a/crates/python_api/src/sfpe_handbook/chapter_50/equation_50_17.rs b/crates/python_api/src/sfpe_handbook/chapter_50/equation_50_17.rs
new file mode 100644
index 0000000..3a72c4f
--- /dev/null
+++ b/crates/python_api/src/sfpe_handbook/chapter_50/equation_50_17.rs
@@ -0,0 +1,46 @@
+use pyo3::prelude::*;
+use pyo3::wrap_pyfunction;
+
+use openfire::sfpe_handbook::chapter_50::equation_50_17 as rust_equation_50_17;
+
+#[pyfunction]
+/// Stairwell temperature calculation for untreated pressurization air.
+///
+/// .. math::
+///
+///    T_S = T_0 + \eta (T_B - T_0)
+///
+/// where:
+///
+/// - :math:`T_S` is the stairwell temperature (°C)
+/// - :math:`T_0` is the outdoors temperature (°C)
+/// - :math:`\eta` is the heat transfer factor (dimensionless)
+/// - :math:`T_B` is the building temperature (°C)
+///
+/// Args:
+///     t_0 (float): Outdoors temperature (°C)
+///     eta (float): Heat transfer factor (dimensionless)
+///     t_b (float): Building temperature (°C)
+///
+/// Returns:
+///     float: Stairwell temperature (°C)
+///
+/// Assumptions:
+///     None stated.
+///
+/// Limitations:
+///     This equation applies to untreated pressurization air. A heat transfer factor of :math:`\eta = 0.15` is suggested in the absence of better data.
+///
+/// Example:
+///     >>> import ofire
+///     >>> result = ofire.sfpe_handbook.chapter_50.equation_50_17.stairwell_temperature(-10.0, 0.15, 15.0)
+///     >>> print(f"{result:.2f}")
+fn stairwell_temperature(t_0: f64, eta: f64, t_b: f64) -> PyResult<f64> {
+    Ok(rust_equation_50_17::stairwell_temperature(t_0, eta, t_b))
+}
+
+#[pymodule]
+pub fn equation_50_17(m: &Bound<'_, PyModule>) -> PyResult<()> {
+    m.add_function(wrap_pyfunction!(stairwell_temperature, m)?)?;
+    Ok(())
+}
\ No newline at end of file
diff --git a/crates/sfpe_handbook/src/chapter_50.rs b/crates/sfpe_handbook/src/chapter_50.rs
index f7dde78..203a463 100644
--- a/crates/sfpe_handbook/src/chapter_50.rs
+++ b/crates/sfpe_handbook/src/chapter_50.rs
@@ -2,6 +2,7 @@ pub mod equation_50_1;
 pub mod equation_50_14;
 pub mod equation_50_15;
 pub mod equation_50_16;
+pub mod equation_50_17;
 pub mod equation_50_18;
 pub mod equation_50_19;
 pub mod equation_50_2;
diff --git a/crates/sfpe_handbook/src/chapter_50/equation_50_16.rs b/crates/sfpe_handbook/src/chapter_50/equation_50_16.rs
index 7f839be..b0a0a9f 100644
--- a/crates/sfpe_handbook/src/chapter_50/equation_50_16.rs
+++ b/crates/sfpe_handbook/src/chapter_50/equation_50_16.rs
@@ -28,4 +28,4 @@ mod tests {
         let expected = 2.035971223;
         assert!((result - expected).abs() < 1e-6);
     }
-}
+}
\ No newline at end of file
diff --git a/crates/sfpe_handbook/src/chapter_50/equation_50_17.rs b/crates/sfpe_handbook/src/chapter_50/equation_50_17.rs
new file mode 100644
index 0000000..79c8523
--- /dev/null
+++ b/crates/sfpe_handbook/src/chapter_50/equation_50_17.rs
@@ -0,0 +1,20 @@
+pub fn stairwell_temperature(t_0: f64, eta: f64, t_b: f64) -> f64 {
+    t_0 + eta * (t_b - t_0)
+}
+
+#[cfg(not(coverage))]
+pub fn stairwell_temperature_equation(t_s: String, t_0: String, eta: String, t_b: String) -> String {
+    format!("{} = {} + {} \\times ( {} - {} )", t_s, t_0, eta, t_b, t_0)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_stairwell_temperature() {
+        let result = stairwell_temperature(-10.0, 0.15, 15.0);
+        let expected = -6.25;
+        assert!((result - expected).abs() < 1e-6);
+    }
+}