This tutorial explains in depth how to sample on CalCERTS. Please read our Sampling FAQ for quick answers to most sampling questions. All FAQ answers are also covered in this tutorial.
These sampling procedures are outlined in the Energy Code in RA 2.6.
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What Is Sampling?
Sampling allows one building's CF-3Rs to count for multiple, similar buildings that have been self-tested by the installer. This enables a HERS Rater to test just one building, but pass other buildings at the same time. This function is essential for big, multi-orientation projects such as tract homes or apartment buildings which feature very similar testing environments.
The idea behind sampling is this: if a contractor correctly installs a mechanical system once, they likely did just as good of a job on every other building. Instead of testing every single building in an apartment, for instance, a HERS rater can take "samples" of the total building by testing a limited number of units. The assumption is, if the tested units were successful, then the other units would also be successful (if tested).
This article refers to dwellings as units and lots interchangeably. Both terms refer to a single dwelling home; units are found in multi-family projects and lots in multi-orientation.
In Alterations, instead of sampling dwelling units, systems are sampled, as each system in an Alteration project constitutes its own project and its own set of CF-2Rs.
Why Do I Want To Sample?
The rater spends far less time on the job site since the rater is only testing a portion of all units. Installers will still test every unit in order to complete the CF-2Rs. Sampling also reduces the amount of paperwork the HERS rater has to do because the registry automatically reports the results of a sample test to every other unit within its sample group.
What Are The Rules For Sampling?
Any building or residence can be sampled together as long as they share a few features:
Every dwelling in a sample group must have the same:
- HERS-tested measures, i.e. CF-3R tests
- Installer/Builder for the Mechanical forms
- Company Controlling the project
Every dwelling eligible to sample must also have:
- A fully-tested model unit for its plan (multi-orientation projects only)
- Been self-tested by the installer
- All mechanical CF-2R forms must be submitted and signed
Things like differences in floor plan, bedroom count, building department, and system weights between units do not matter.
Note: If a unit passes a refrigerant charge test based on a weighed-in charge, then that unit's MCH-25 test is ineligible for sampling. The unit can still sample based on its other tested measures.
Note: Units can be grouped into samples even if its CF-2Rs are pending payment. Payment must be made before the group can be tested, however.
What Is A Model?
A model is the first dwelling created for a plan. It is proof that the design works. Sometimes these dwellings are utilized as example homes for the developers or potential buyers, but not always. Any unit can be considered a model as far as CalCERTS is concerned.
In order to sample multi-orientation projects, every plan requires one model unit as a baseline for every plan associated to units that are going to be sampled. The model unit must have fully-completed CF-3Rs. Models cannot be a part of sample groups.
Although sampling requirements are satisfied with just one fully-completed model, the registry allows users to select more than one model per plan. It is entirely unnecessary to have more than one model unit per plan. If more than one model is indicated for a plan, not just one but every model must be fully completed before any unit using the plan can be sampled.
How Do I Assign Models?
Lots in a multi-orientation project can be assigned as models on the Lots page.
Units in a multi-family project can be assigned as models on the Units page.
Click on the orange hexagon. On the Lots/Units page, simply click on the No button to toggle it to "Yes" and assign it as a model.
Buildings can be assigned as models from the CF-1R page on the Buildings tab. Simply select the radio button next to a building to mark it as a model.
How Do I Create A Sample Group?
Click on the dark green Sample hexagon at the top of the page to begin establishing sample groups. Any unit/lot that is available for sampling will be on this page.
Click on the button in the far-right column to start a sample group with that unit/lot. On the next page, any units/lots that are currently available to be in a sample group with the unit/lot selected prior.
If a unit/lot is not on this list, it does not comply with the Rules For Sampling; double-check the unit/lot has fully-completed CF-2Rs, a fully-tested model (if necessary), and the same HERS measures as the other lots. See the Sampling Tool section for more help.
Open Sample Group vs. Closed Sample Group
There are two types of sample groups - open and closed. Each group type has advantages and disadvantages.
Closed sample groups are simple. When creating a sample group, you can add up to 7 units to a group. The group must be established before any CF-3Rs are submitted. If no CF-3R certificates are submitted, users can edit the closed sample group at any time. An untest of all CF-3Rs in a closed sample will allow users to edit a closed sample group on the Sample page.
Open sample groups are more complicated. You may only have up to 5 units in an open group sample. The advantage is, you may continue to add units to a (max 5 unit) group even after the tested lot is reported. This is useful for on-going projects where more dwellings are being added to the project over time and the whole sample group can't be established immediately.
There are more rules in regard to open group sampling: CF-2R signatures cannot be over 180 days old. None of the units in the sample group or potential units can have CF-2R signatures over 180 days. This only applies to open group sampling.
Finally, open sample groups cannot be modified, even with no CF-3Rs present. Once a unit is placed into an open sample group, it cannot be removed from the group. Users are unable to break up or modify open sample groups - users can only add units to the group, up to a maximum of 5 units.
How Do I Report Results On Sample Groups?
Click on the blue hexagon to view the CF-3Rs; any lot/unit within a sample group will be fine. At the top of the page, every lot/unit within the sample group will be featured at the top of the page. Click on the lot/unit that is going to be the tested leader, the sampled lot.
Simply click on Report Results to report CF-3R test results. Through the magic of sampling, every other lot/unit within the sample group will be reported on simultaneously. The sampled units' PDF reports will indicate that it was certified from being in a sample group.
Why Can't I Sample These Lots? Why Isn't One Of My Lots Able To Sample?
Lots/units must have fully tested CF-2Rs in order to be sampled. The unit's project must also be active and not archived.
Units/lots will only appear on the Sample page when the CF-2Rs are all complete (and in the case of multi-orientation/multi-family) when that unit/lot's model is fully tested with complete CF-3Rs.
After clicking on the button for a particular lot/unit to be sampled, the lot/unit may only be associated with the exact same HERS measures, the same builder/installer on the CF-2Rs, and the same rater assigned.
Use the Sampling Tool to compare the sampling details of two lots together. This tool explains exactly why two lots can or cannot sample together.
Choose two lots from the drop-down menus, then click Compare. The next page is a breakdown of every detail necessary for sampling. Any discrepancies are clearly indicated in red text.
Here's an example of two lots that are ready to be sampled together. They share the same plan and that plan has a fully-completed model. Both lots have all MCH forms submitted and signed but no CF-3Rs started.