Alternate Work Practice (AWP): Overview and Terms
Published: 2026-07-21 Revised: 2026-10-28
The Alternate Work Practice (AWP) lets a downstream facility survey its equipment with an Optical Gas Imaging (OGI) camera instead of monitoring every component individually with a Method 21 (M21) analyzer. It is the Method 21 Alternative Work Practice: a facility that would otherwise run a traditional, fully M21 monitoring program can instead walk its areas with an OGI camera along a defined route.
Two ways to record an AWP survey
Chateau has two methods for recording an AWP survey. For a short transition period both are available. The milestone method will then be retired.
| Area survey (new) | Milestone method (being retired) | |
|---|---|---|
| What defines the survey | A tour: the survey covers the tour's components, grouped however suits the facility (by area, unit, REN…) | A route through the area, in route sequence or tag order |
| What the technician records | Only leaks, components they couldn't monitor, and components they didn't get to | Milestone inspections along the route, plus leaks |
| How the other components get inspected | When the survey is completed, Chateau creates a passing OGI inspection for every component with no leak, no Did Not Monitor, and not left for later | Chateau creates path inspections for the components between each pair of milestones |
| Route sequence needed | No | Yes |
| Survey record | Yes. Each survey appears under OGI › Surveys with its video, sensitivity check, counts and GPS track. | No |
New AWP programs should use area surveys. See AWP Area Surveys: Overview, Recording an AWP Area Survey in Chateau Mobile and Reviewing AWP Area Surveys in Chateau.
The rest of this article describes the milestone method.
The milestone method
Instead of navigating to and recording a result on every component, the technician walks a defined route through the area while scanning with the OGI camera and records Milestone Inspections at intervals along the way. Chateau then automatically creates Path Inspections for all of the components between each pair of milestones, on the basis that they were surveyed as the technician walked past them.
AWP vs. a traditional Method 21 program
AWP is used by downstream facilities as an alternative to their traditional, component-by-component Method 21 program:
| Traditional Method 21 program | AWP | |
|---|---|---|
| Approach | Monitor every component individually with an M21 analyzer | Walk a route with an OGI camera; record milestones at intervals |
| What the technician records | A PPM reading on every component | A result only on milestone components |
| Components in between | Each monitored directly | Path Inspections created automatically |
AWP is enabled per facility. For large facilities, surveying areas with an OGI camera can be more cost-effective than monitoring every component individually with an M21 analyzer.
Key terms
| Term | Definition |
|---|---|
| AWP (OGI) Inspection | An OGI inspection assigned by Chateau Rules that must be performed in compliance with the Alternate Work Practice. Appears in Rules as OGI Annual / Semiannual / Quarterly / Bimonthly / Monthly. |
| Milestone Inspection | An OGI inspection the technician records manually on a specific component to mark a point in the survey — typically the start and end of a session, or at a set time interval. Milestones define the boundaries used to create Path Inspections. |
| Path Inspection | An OGI inspection Chateau creates automatically for a component that lies between two milestones, on either the Route Sequence or Tag Number order. It is not physically performed — it is inferred from the technician's survey path. |
| Session | The period between two consecutive milestone inspections (one starting, one ending). |
| Milestone Interval | The number of minutes after which the technician is reminded to record another milestone. Set per technician. New technicians default to 800 minutes, which effectively turns the timed reminder off — leave it there if milestones are placed by physical area/section, or lower it to remind the technician on a time (video-length) cadence. See Setting Up AWP. |
| Starting / Ending Milestone | The first milestone opens a session; the next milestone closes it and triggers Path Inspection creation for the components in between. |
| Area Survey | A survey of one tour's components in Chateau Mobile. When it is completed, Chateau creates a passing OGI inspection for every component with no leak, no Did Not Monitor, and not left for later. See AWP Area Surveys: Overview. |
| Survey Video | The video of the whole survey, kept with it as proof the tour's components were surveyed |
How the pieces fit together
- An administrator turns on AWP mode and configures the survey settings — see Setting Up AWP.
- In the field, the technician records milestones as they survey, and Chateau fills in the path inspections between them — see Recording an AWP Survey.
- Leaks found mid-survey are recorded as standard OGI failures, not milestones — see Handling Leaks During an AWP Survey.
- Milestone and path inspections can be corrected back in the office — see Editing and Deleting AWP Inspections.
- Survey media, reporting, and compliance checks pull it all together — see AWP Media, Reporting, and Compliance.