ASHRAE Guideline 36-2018: High-Performance Sequences of Operation for HVAC Systems
About this book
ASHRAE Guideline 36, "High-Performance Sequences of Operation for HVAC Systems," provides standardized control sequences and programming specifications for HVAC systems in commercial buildings. Unlike ASHRAE standards (which establish minimum requirements), guidelines represent recommended best practices, and Guideline 36 represents perhaps the most ambitious attempt ever made to standardize the operational intelligence of building mechanical systems. The guideline emerged from research demonstrating that HVAC systems, even when designed and installed correctly, frequently underperform their theoretical capacity due to poorly written control sequences.
A study by Lawrence Berkeley National Laboratory found that implementing the sequences in Guideline 36 could reduce energy consumption in commercial buildings by 29 percent compared to typical control practice — a finding that gave the guideline significant industry traction. Guideline 36 provides detailed sequences for variable air volume (VAV) systems with parallel fan-powered and series fan-powered terminals; air handling units including dual-duct, single-duct, and dedicated outdoor air systems; chilled water plants with variable speed pumping; boiler plants; central cooling and heating plants; and fan coil units. Each sequence specifies not just the control logic but also the tuning parameters, alarm conditions, and commissioning verification tests required to ensure correct implementation.
A key innovation in Guideline 36 is its specification in a format compatible with direct digital control (DDC) systems, allowing it to be translated into manufacturer-agnostic programming code. This addresses the historical problem of HVAC controls being locked into proprietary sequences that cannot be easily audited, verified, or transferred to new systems. The 2018 edition was a landmark publication that defined the field.
It has been adopted as the basis for HVAC controls specifications on high-performance building projects across the United States, and is referenced in numerous green building standards and guidelines. OpenADR and other demand response frameworks have begun incorporating Guideline 36 sequences as the baseline for demand flexibility programming. Sources: ASHRAE (ashrae.org); Lawrence Berkeley National Laboratory (lbl.gov); ASHRAE Guideline 36-2018 official publication.