ISO 13579-11:2017

Overview - What ISO 13579-11:2017 covers

ISO 13579-11:2017 provides a standardized methodology for evaluating the energy performance of industrial furnaces and associated processing equipment (TPE). The standard defines classifications and designations used when measuring energy balance and calculating energy efficiency both in terms of enthalpy (heat) and exergy (available energy). It clarifies boundaries for evaluation, describes components of energy and exergy flows, and sets out measurement and reporting practices to support consistent, comparable assessments.

Scope exclusions (not covered): blast furnaces, basic oxygen furnaces, coke ovens; furnaces producing fuel gases; special atmosphere gas generators; furnaces in chemical or petroleum plants; open-space combustion installations; solid-fuel combustion units; and waste incinerators.

Key technical topics and requirements

• Energy balance and boundary definition - classification of evaluation areas and how to treat energy (enthalpy) flows into and out of the system.
• Components of energy accounting - energy input to the heating chamber, process energy, exhaust sensible heat, recovered heat, thermal losses, electrical/electroheating losses, auxiliary equipment, utilities generation and recycled energy.
• Enthalpy-based efficiencies - general formulas and typical efficiency definitions (overall efficiency, heat efficiency, combustion efficiency, recovery ratios).
• Exergy-based efficiencies - classification and calculation of exergy flows (fuel exergy, electrical exergy, exergy of reactions, exhaust exergy, recovery exergy and exergy losses) and exergy-efficiency metrics for fair comparison across processes.
• Designation system and reporting - structured naming/labeling for items and operations, measurement procedures, and format for the evaluation report.
• Practical guidance and tools - informative annexes with worked examples (energy efficiency evaluation, enthalpy vs. exergy comparisons, and procedures for estimating energy savings).

Practical applications - who uses this standard

ISO 13579-11:2017 is used by:

• Plant and furnace designers to benchmark thermal system performance.
• Energy managers and sustainability teams to quantify savings and prioritize upgrades.
• Process engineers and maintenance teams to identify recovery opportunities (heat recovery, reduced losses).
• Energy auditors, certification bodies, and consultants assessing compliance, CDM projects or energy-efficiency investments.
• Equipment manufacturers and system integrators seeking consistent efficiency metrics for product claims.

Benefits include consistent energy accounting, improved decision-making for retrofits, fair comparisons between furnace types and operating modes, and better alignment with energy-saving programs.

Related standards

• ISO 13579 series (Parts 1–4 and others) - broader methods for furnace energy evaluation.
• ISO 13574:2015 - vocabulary for industrial furnaces and associated processing equipment.

Keywords: ISO 13579-11:2017, industrial furnaces, energy efficiency, energy balance, enthalpy, exergy, heat recovery, TPE evaluation, measurement and reporting.