Air Quality Dispersion Modelling to Evaluate CIPP Installation Styrene Emissions

Area of Science:

• Environmental Engineering
• Occupational Health
• Chemical Engineering

Background:

• Cured-in-place pipe (CIPP) is a common trenchless pipe repair method.
• Steam-curing of styrene-based resins in CIPP can release airborne chemicals, notably styrene.
• Concerns over styrene emissions necessitate further investigation into CIPP site safety.

Purpose of the Study:

• To model worst-case styrene emissions from steam-cured CIPP installations.
• To assess styrene concentrations relative to health and safety thresholds.
• To evaluate the adequacy of current safety perimeters for CIPP sites.

Main Methods:

• Utilized AERMOD dispersion modeling software.
• Modeled styrene emissions from two US CIPP installation sites.
• Calibrated the model using work-day average emissions, not instantaneous measurements.

Main Results:

• Styrene emissions from stacks dissipate rapidly.
• Concentrations exceeded safety thresholds only within 2 meters of the stack.
• Predicted concentrations align with previously measured field data.

Conclusions:

• Significant health impacts are unlikely beyond the recommended 4.6-meter safety perimeter.
• The study validates the importance of adhering to current safety guidelines for steam-cured CIPP.
• Effective emission control and safety perimeters are crucial for CIPP operations.