Mechanical and Maintenance Engineering


This is a brief introduction to the technical documentation issued by Mechanical and Maintenance Engineering that relates to Public Works and Government Services Canada (PWGSC) buildings. The documentsFootnote 1 are:


These documents apply to all built works undertaken by or for PWGSC, including new construction, existing buildings, renovations, and/or fit- up. They apply to crown-owned buildings, leased premises or Alternate Form of Delivery (AFD) managed facilities, delivered by PWGSC or its agents either directly or indirectly through third party arrangements.

Technical Documentation

MD 15116-2006 "Computer Room Air Conditioning Systems" provides general guidance for the design of mechanical systems for computer rooms, server rooms, telecom rooms and data centres as used in PWGSC buildings. These special areas form an integral part of most PWGSC buildings and often perform "mission critical" functions, including the handling sensitive data on a 24/7 basis. As a result, the mechanical design requirements for these systems are very different from the requirements for the rest of the building. MD 15116-2006 addresses the issues that are specific to these type of facilities.

Mechanical Design Guideline MD 15116-2006 "Computer Room Air Conditioning Systems" provides general guidance for the design and operation of mechanical systems for computer rooms, server rooms, LAN rooms, telecom equipment rooms and data centers. This guideline is intended for use in new projects as well as for the retrofits of existing buildings.

MD 15161-2006 "Control of Legionella in Mechanical Systems"

outlines the requirements for the design, maintenance and operation of mechanical systems in PWGSC buildings to minimize the occurence of Legionella. Recent outbreaks of the disease have highlighted the need for effective control measures. In most cases, the source of the outbreak has been traced to the building's mechanical systems. Cooling towers have been implicated in some cases while, in others, the outbreak has been attributed to the potable water systems. As MD 15161-2006 points out, proper operation and maintenenance of the mechanical systems with regular disinfection procedures is the key to Legionella control.

MD 15128 "Laboratory fume hoods: Guidelines for owners, design professionals and maintenance personnel" (2008)

is intended to provide a consistent approach to the specification, testing, operation, and maintenance of laboratory fumehoods in PWGSC managed facilities and in other Government of Canada laboratories. The guidelines describe the requirements for bypass, variable air volume, and, high performance laboratory fumehoods only. The guidelines do not apply to specialized equipment such as biological safety cabinets or laminar flow clean benches. For perchloric acid fume hoods, refer to MD 15129 (2006) below.

MD 15129 "Guidelines for Perchloric Acid fumehoods and their exhaust systems" (2006)

outlines the requirements for building, operating, and maintaining perchloric fume hoods in laboratories. The perchloric acid fumehood is one of the most distinctive pieces of equipment found in laboratories. While perchloric acid is useful for certain analytical procedures, it brings with it the potential for some dangerous repercussions due to the formmation of perchlorates within the fume hood, ductwork and /or exhaust fan. Perchlorates are extremely shock sensitive and can explode very easily. Hence perchloric acid fumehoods should be designed, installed, maintained and decommissioned very carefully. MD 15129 offers detailed guidance for doing this. This document is complementary to MD 15128 "Laboratory fume hoods: Guidelines for owners, design professionals and maintenance personnel" (2008). The objectives of MD 15129 match closely with commissioning objectives in laboratory projects. It is important that commissioning personnel be familiar with the contents of MD 15129.

PWGSC Best Practice "Prescribing indoor humidity levels for federal buildings" (2006)

addresses the problems resulting from the release of ASHRAE Standard 55-2004"Thermal Environmental Conditions for Human Occupancy". Earlier editions of the ASHRAE Standard prescribed both minimum and maximum humidity levels for buildings, but ASHRAE Standard 55-2004 has dropped the requirement for minimum humidity. The PWGSC Best Practice has been developed to provide recommendations for minimum humidity levels, after a detailed analysis of the issues involved.

Other documents that will be issued very shortly by Mechanical and Maintenance Engineering include the EMCS design manual, and the Mechanical Design Standard for Air Filtration.

MD 250005-2009 "Energy Monitoring and Control Systems (EMCS) Design Guidelines"

Energy Monitoring and Control System (EMCS) Design Guidelines were first published by the Department of Public Works, as it was then called, in 1984 in response to a need for an orderly approach to the design of these sytems. The document was intended for Engineers, Technologists, and Consultants involved in the design of EMCS.

Since then, many technological advances and changes have occurred resulting in the need to revise and update this document. In addition, considerable experience in the design, installation and operation of EMCS has been gained and these have resulted in the need to revise the document.

The previous designation number of the document, MD 13800, has now been replaced with MD 250005-2009 to reflect the new specification sections in the revised National Master Specifications issued by PWGSC.


Technical inquiries about the documentation isssued by Mechanical and Maintenance Engineering should be directed to:

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