Reaching Forward to Subsequent Monitoring Events

Another option you may encounter when setting up emissions calculations is “Reach Forward.” This setting applies only to components that were monitored during the reporting period, but which do not have a monitoring event that falls exactly on the calculation period’s end date.

Normally, if no inspection exists on the final day of the calculation period, Chateau will use the most recent inspection prior to the end date and carry that reading forward through the end of the period. While this is a valid approach, it can sometimes underestimate or overestimate emissions if a new monitoring event occurred shortly after the calculation period closed.

The Reach Forward option addresses this by allowing the database to look ahead in time, beyond the end date of the calculation window, and use the next available monitoring event as the “end point” for the calculation. This option assumes that the calculation period is in the past and that subsequent monitoring data already exists in the database.

How Chateau Implements Reach Forward

When you set up your Emission Model in Chateau, you can choose the option:

“Reach Forward to get subsequent (only for monitored in period).”

• If selected, Chateau will search forward beyond the calculation period’s end date to locate the next monitoring event for that component.
• If such an event is found, Chateau will use that reading as the effective end PPM for the reporting period being calculated.
• If no subsequent reading exists, Chateau will continue to use the last reading within the calculation period and carry it through the end date as normal.

Example:

• You are calculating emissions for calendar year 2024.
• A valve was monitored in September 2024, but not again until February 2025.
• With Reach Forward disabled, Chateau would apply the September 2024 reading through December 31, 2024.
• With Reach Forward enabled, Chateau would “look ahead” and use the February 2025 reading as the end point for December 31, 2024, giving a more accurate transition into the next period.

Why Use Reach Forward?

The Reach Forward option provides a more realistic estimate for the end of the calculation period by ensuring that your data does not artificially “freeze” at the last in-period inspection. This helps:

• Capture more accurate trends for components that are monitored late in the year.
• Prevent inflated emissions estimates caused by a pegged or high reading on a component that wasn’t inspected again until shortly after the reporting period ended.

Maintain consistency when comparing year-to-year emissions, especially if monitoring schedules shift slightly.