ANSI IES LP-3-20 PDF

Full title and description

ANSI/IES LP-3-20 — Lighting Practice: Designing and Specifying Daylighting for Buildings. A Lighting Practice document from the Illuminating Engineering Society that provides guidance on the integrated design, performance, and specification of daylighting systems for buildings, covering daylight delivery methods, fenestration and shading systems, integration with electric lighting and controls, and performance simulation tools.

Abstract

This American National Standard describes principles and practical guidance for admitting and controlling sunlight and skylight to meet visual and non-visual needs, balance occupant comfort and energy performance, and integrate daylighting with electric lighting and building systems. It includes design parameters, fenestration technology discussion, shading and framing considerations, control strategies, and an annexed formulary for daylight calculations.

General information

• Status: Published American National Standard (ANSI/IES LP-3-20).
• Publication date: 2020.
• Publisher: Illuminating Engineering Society (IES).
• ICS / categories: Lighting — ICS 91.160 (lighting).
• Edition / version: LP-3-20 (with Errata 1 indicated as +E1).
• Number of pages: 149 pages.

Scope

Provides comprehensive guidance for the design and specification of daylighting systems in buildings. Topics include benefits and challenges of daylighting, context and design parameters, daylight delivery methods, fenestration and glazing systems, shading and frame systems, strategies for electric lighting integration and controls, and methods and tools for daylight performance simulation and evaluation. The guidance is intended to support designers in achieving visual comfort, energy efficiency, and occupant wellbeing through properly engineered daylighting solutions.

Key topics and requirements

• Daylighting design principles: balancing daylight availability with visual comfort and glare control.
• Context and site parameters: orientation, climate, and adjacent reflections affecting daylight performance.
• Fenestration technologies: window types, glazing performance, coatings, and daylight transmittance.
• Shading and frame systems: operable and fixed shading strategies to control solar gains and glare.
• Electric lighting integration and controls: daylight-responsive dimming, commissioning, and control strategies for energy savings and occupant needs.
• Daylight modelling and performance tools: recommended simulation approaches and a formulary for common calculations (annex material).
• Specification guidance: recommended metrics, documentation practices, and criteria for product selection and acceptance.

Typical use and users

Used by architects, lighting designers, electrical and mechanical engineers, façade consultants, window and shading product manufacturers, building owners, facility managers, and code or standards practitioners. Typical uses include developing daylighting strategies during schematic and detailed design, preparing specifications and performance criteria, selecting fenestration and shading systems, integrating controls with electric lighting, and validating performance with simulation and commissioning.

Related standards

Part of the IES Lighting Practice collection and complements other IES documents such as ANSI/IES LP-1-20 (Designing Quality Lighting for People and Buildings), ANSI/IES LP-2-20 (Designing Quality Lighting for People in Outdoor Environments), and ANSI/IES LP-4-20 (Electric Light Sources — Properties, Selection, and Specification). It also aligns with IES recommended practices and technical memoranda that address controls, color rendition, and lighting calculation methods.

Keywords

daylighting, fenestration, glazing, shading, daylight simulation, electric lighting integration, daylight controls, daylight performance, building design, LP-3-20

FAQ

Q: What is this standard?

A: ANSI/IES LP-3-20 is a Lighting Practice standard published by the Illuminating Engineering Society that provides guidance for designing and specifying daylighting systems in buildings. It is an American National Standard developed through the IES ANSI-accredited process.

Q: What does it cover?

A: It covers daylighting benefits and challenges, design and context parameters, delivery methods (windows, skylights, light shelves, etc.), fenestration and glazing choices, shading and framing systems, integration with electric lighting and controls, performance simulation methods, and a formulary for common daylight calculations.

Q: Who typically uses it?

A: Architects, lighting designers, façade engineers, electrical/mechanical engineers, product manufacturers, facility managers, and specifiers use LP-3-20 for design guidance, specification writing, product selection, simulation practices, and commissioning criteria related to daylighting.

Q: Is it current or superseded?

A: The LP-3-20 edition was published in 2020; the document is current as published but has an Errata 1 (+E1) and errata postings available from IES. Users should check for the latest errata or amendments before final specification use.

Q: Is it part of a series?

A: Yes. LP-3-20 is part of the IES Lighting Practice (LP) collection of standards and is intended to be used in conjunction with other IES LP, RP, TM, and LS documents that address lighting practice, recommended practice, technical memoranda, and lighting science.

Q: What are the key keywords?

A: Daylighting, fenestration, glazing, shading, daylight simulation, daylight controls, electric lighting integration, daylight metrics, daylight performance.