Measure Overview
A process steam system is a steam-producing boiler system that serves loads other than space heating or service water heating for human occupants, such as manufacturing or industrial processes. A condensate return system, consisting of piping, collection tanks, and pumps, returns hot condensate—which is generated after process loads use steam—to the boiler system for reuse.
This proposed measure would require newly constructed process steam systems and newly added process steam loads that a) use indirect-contact heat exchangers and b) generate condensate during normal operation to return steam condensate to the boiler for reuse via a condensate return system. Qualifying process steam systems must also return condensate from associated drip legs.
The proposed measure would only apply to steam systems that meet certain criteria for load size and condensate return piping lengths. Condensate return from direct steam injection (that comes in direct contact with the process) would be exempt from the requirement for condensate return.
To meet the criteria for load size and condensate return piping lengths, the linear distance from the load to the condensate return tank or the deaerator, measured across both horizontal and vertical dimensions, must be under a maximum length depending on the system steam flow. The distances for each steam flow range of the individual load are specified in Table 18.
Table 1: Condensate Return Code Trigger Criteria
| Steam Flow (lb/h) | Linear Length1 (ft) less than |
| <1,000 | Exempt |
| ≥1,000, <2,000 | 400 |
| ≥2,000, <3,000 | 600 |
| ≥3,000, <4,000 | 800 |
| ≥4,000, <6,000 | 1,100 |
| ≥6,000 | 1,300 |
All steam loads that are above the maximum length for their steam flow shall include the condensate return distance calculations from NA9 in the steam system construction documents to prove that the requirement is not applicable to that steam load.
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Scope of Proposed Code Change
| Building Type(s) | Construction Type(s) | Type of Change | Updates to Compliance Software | Third Party Verification |
| Nonresidential | New construction, additions, alterations | Mandatory | No updates | No changes to third party verification |
Justification for Proposed Change
In process steam systems, condensate is formed when steam releases its heat of condensation in a heat exchanger and condenses into liquid. Facilities that recover condensate reduce the need for make-up water, pre-heating fuel, and chemicals for water treatment. Some sites may also benefit from a reduction in wastewater costs. Because condensate is effectively distilled water, its recovery also reduces the need for boiler blowdown, which results in additional energy savings.
Department of Energy (DOE) literature has recommended increasing the percentage of returned condensate as a steam system best practice in since at least the early 2000s, and the DOE provides a steam tip sheet specifically on improving condensate return. This proposed code change originated from discussions with California-based consulting engineers from strategic energy management programs and the DOE Industrial Assessment Center program.
Depending on site conditions, this measure is expected to yield energy savings of approximately 5% to 8% of baseline boiler system fuel use. There are two main sources of savings: (1) the energy difference between returned condensate and cold makeup water and (2) reduced blowdown losses resulting from increased condensate return.
To the knowledge of the Statewide CASE Team, condensate return requirements have not been proposed in previous code cycles. In 2013, Title 24 Part 6 first adopted requirements for process boilers. In 2022, Title 24 Part 6 adopted requirements for strainers and fault detection and diagnostics in steam trap assemblies.
Relevant Documents
Round One Utility-Sponsored Stakeholder Meeting Materials
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The Statewide CASE Team values input from all stakeholders engaged in the Title 24, Part 6 code change process. We encourage the open exchange of code change comments and concerns.