SNT 3.05.02-94 PDF

Full title and description

SNT 3.05.02-94 — Heating, Ventilation and Air Conditioning (HVAC) systems for buildings, with specific provisions addressing staircase ventilation and pressurization for smoke protection and emergency egress. The document defines functional requirements for stairwell pressurization, ventilation rates, basic fan and control arrangements, and integration with fire-detection/alarms to preserve tenable escape routes in the event of fire.

Abstract

This standard (SNT 3.05.02-94) provides technical requirements and recommendations for the design, installation and operation of HVAC systems that affect staircases and other vertical egress enclosures. It covers means to prevent smoke entry to exit routes using pressurization and ventilation measures, describes performance and operational considerations for fans and control strategies, and indicates interactions with building fire‑safety systems. It is intended to support safe evacuation and smoke control strategies in multi‑storey buildings.

General information

• Status: National technical standard (SNT series) recorded in national regulatory libraries; used as a normative design reference for HVAC and smoke‑control measures.
• Publication date: 1994 (denoted by the "-94" suffix in the document identifier).
• Publisher: Issued under the SNT (national technical norms) framework and distributed through national/regional standards and regulatory libraries. Specific issuing body is the SNT/technical norms authority recorded in the national repository.
• ICS / categories: Heating, ventilation and air conditioning; fire safety and smoke control; building services engineering.
• Edition / version: Edition indicated by the year code: original 1994 edition (SNT 3.05.02-94). Current revision status should be checked with the national standards body for updates or supersession.
• Number of pages: Not specified in public summary records available in standard repositories; format is typically a technical booklet (PDF/DOC) — page count varies by publisher.

Scope

SNT 3.05.02-94 addresses design and operational requirements for HVAC installations that affect means of egress, with emphasis on staircases and other vertical evacuation enclosures. The scope includes requirements for delivering and controlling supply air to stair enclosures (pressurization), limiting pressure differentials to acceptable door opening forces, fan selection and distribution (single or multiple injection points), activation logic in conjunction with fire detection, and commissioning/acceptance criteria to demonstrate effective smoke exclusion during fire conditions. The standard is aligned with common smoke‑control objectives used in international HVAC practice.

Key topics and requirements

• Definition of stairwell pressurization objectives and acceptable pressure differentials to maintain tenability while keeping door opening forces within ergonomic limits.
• Guidance on supply‑air quantities and fan sizing approaches for stair pressurization, including use of single or multiple injection points depending on stair geometry and height.
• Requirements for locating and protecting fresh‑air intakes (separation from building exhausts and smoke sources).
• Control and activation sequences tied to fire detection — start/stop logic for pressurization fans and interaction with alarms and smoke detectors.
• Commissioning, means of verification, and operational checks to confirm that stair pressurization performs under realistic door‑opening and leakage conditions.
• Integration notes with overall building smoke‑control strategies and references to related national/regional fire and HVAC codes.

Typical use and users

Primary users are building services engineers, HVAC designers, fire‑safety engineers, consultants, and commissioning agents working on multi‑storey residential, commercial and public buildings where protected stairwells or pressurized egress routes are required. Authorities having jurisdiction, building inspectors and project design teams use the standard as a technical reference when specifying stair ventilation and pressurization measures. Guidance provided is consistent with international engineering practice for stairwell pressurization and smoke control.

Related standards

Related and commonly referenced documents include national SNT/SNiP/SNIP building and HVAC codes (for example SNiP/SN references on HVAC and smoke control), international documents on smoke control and pressurization (for example EN 12101 series and NFPA guidance), and regional building codes that set evacuation and fire‑safety requirements. Project teams typically cross‑reference SNT 3.05.02-94 with SNIP/SNiP 2.04.05‑91 (HVAC requirements for smoke control) and international practice standards.

Keywords

SNT 3.05.02-94; HVAC; stairwell pressurization; stair ventilation; smoke control; pressurization systems; fire safety; building services; commissioning; ventilation rates.

FAQ

Q: What is this standard?

A: SNT 3.05.02-94 is a national technical standard covering heating, ventilation and air conditioning (HVAC) provisions related to staircases and pressurization for smoke protection, published in 1994 under the SNT series of technical norms.

Q: What does it cover?

A: It covers requirements and recommendations for staircase ventilation and pressurization systems (fan arrangements, supply air distribution, control logic with fire detection, acceptable pressure limits, and commissioning tests) to maintain protected egress during a fire.

Q: Who typically uses it?

A: HVAC and fire‑safety engineers, building services designers, consultants, commissioning agents, and regulatory authorities use the standard when designing or reviewing stairwell pressurization and related smoke‑control systems.

Q: Is it current or superseded?

A: The document is the 1994 edition (SNT 3.05.02-94). Public record references show the 1994 SNT listing in national repositories, but availability of later revisions or national superseding acts may vary by jurisdiction. Users should verify current status with the national standards authority or local building code office before relying on it for compliance.

Q: Is it part of a series?

A: Yes — it belongs to the SNT series (national technical norms) for building services and HVAC; related documents in the same numbering block address other HVAC, ventilation and building service topics (see other SNT 3.0x documents and related SNIP/SNiP codes).

Q: What are the key keywords?

A: HVAC, stairwell pressurization, smoke control, pressurization fan, ventilation rates, escape route protection, SNT 3.05.02-94.