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10 CFR § 431.86 - Uniform test method for the measurement of energy efficiency of commercial packaged boilers.

---
identifier: "/us/cfr/t10/s431.86"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "10 CFR § 431.86 - Uniform test method for the measurement of energy efficiency of commercial packaged boilers."
title_number: 10
title_name: "Energy"
section_number: "431.86"
section_name: "Uniform test method for the measurement of energy efficiency of commercial packaged boilers."
chapter_name: "DEPARTMENT OF ENERGY"
subchapter_number: "D"
subchapter_name: "ENERGY CONSERVATION"
part_number: "431"
part_name: "ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "42 U.S.C. 6291-6317; 28 U.S.C. 2461 note."
regulatory_source: "64 FR 54141, Oct. 5, 1999, unless otherwise noted."
cfr_part: "431"
---

# 431.86 Uniform test method for the measurement of energy efficiency of commercial packaged boilers.

(a) *Scope.* This section provides test procedures, pursuant to the Energy Policy and Conservation Act (EPCA), as amended, which must be followed for measuring the combustion efficiency and/or thermal efficiency of a gas- or oil-fired commercial packaged boiler.

(b) *Testing and Calculations.* Determine the thermal efficiency or combustion efficiency of commercial packaged boilers by conducting the appropriate test procedure(s) indicated in Table 1 of this section.

Table 1—Test Requirements for Commercial Packaged Boiler Equipment Classes

| Equipment category | Subcategory | Certified rated inputBtu/h | Standards efficiency metric(§ 431.87) | Test procedure(corresponding tostandards efficiencymetric requiredby § 431.87) |
| --- | --- | --- | --- | --- |
| Hot Water | Gas-fired | ≥300,000 and ≤2,500,000 | Thermal Efficiency | Appendix A, Section 2. |
| Hot Water | Gas-fired | >2,500,000 | Combustion Efficiency | Appendix A, Section 3. |
| Hot Water | Oil-fired | ≥300,000 and ≤2,500,000 | Thermal Efficiency | Appendix A, Section 2. |
| Hot Water | Oil-fired | >2,500,000 | Combustion Efficiency | Appendix A, Section 3. |
| Steam | Gas-fired (all*) | ≥300,000 and ≤2,500,000 | Thermal Efficiency | Appendix A, Section 2. |
| Steam | Gas-fired (all*) | >2,500,000 and ≤5,000,000 | Thermal Efficiency | Appendix A, Section 2. |
|  |  | >5,000,000 | Thermal Efficiency | Appendix A, Section 2.ORAppendix A, Section 3 with Section 2.4.3.2. |
| Steam | Oil-fired | ≥300,000 and ≤2,500,000 | Thermal Efficiency | Appendix A, Section 2. |
| Steam | Oil-fired | >2,500,000 and ≤5,000,000 | Thermal Efficiency | Appendix A, Section 2. |
|  |  | >5,000,000 | Thermal Efficiency | Appendix A, Section 2.ORAppendix A, Section 3. with Section 2.4.3.2. |
| * Equipment classes for commercial packaged boilers as of July 22, 2009 (74 FR 36355) distinguish between gas-fired natural draft and all other gas-fired (except natural draft). |  |  |  |  |

(c) *Field Tests.* The field test provisions of appendix A may be used only to test a unit of commercial packaged boiler with rated input greater than 5,000,000 Btu/h.

[81 FR 89305, Dec. 9, 2016]