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Enclosure System
One of eight primary systems in a building.

The building enclosure (also known as the building “envelope” or "facade") separates the exterior environment from the interior environment of the building.  It is analogous to the skin on the human body.  


Attributes
The enclosure system has the following general attributes:
    • The enclosure system has the closest relationship with the structural system - to which it is attached. The enclosure system also has localized relationships with the electrical and mechanical systems, particularly at service penetrations through the wall and roof assemblies (such as dryer vents and fireplace vents.
    • The building envelope is only partially accessible, often with several hidden layers or components. The components and materials of the building enclosure are generally exposed to the exterior environment and therefore will deteriorate over time.  Maintenance and renewals of this system is critical not only to the ongoing performance of the building enclosure, but also for the other building systems that the building enclosure protects
    • The assets are generally medium-life assets (such as roofs) and long-life assets (such as cladding and glazing systems). There are also some short life assets (such as paint coatings and balcony membranes).
    • Many of the enclosure assets do not lend themselves well to time-based maintenance (TbM) strategies and are better suited to Condition-based Maintenance (CbM).


    Physical Analysis
    Physical analyses of the systems can be found at:


    Asset Inventory
    Some of the primary assemblies in the enclosure includes assets such as:
    • Roofs
    • Walls
    • Windows
    • Doors
    • Balconies
    • Canopies 
    These assets all serve to separate the exterior from the interior space.

    The photographs to the right show some of the different facets of the enclosure system.



    Survey Questions
    Listed below are some sample questions that are utilized in a facility condition assessment:
    1. Please indicate the locations of any current leaks into the building from the roof, windows, or walls?   
    2. Please indicate the locations of any historical leaks into the building from the roof, windows, or walls? 
    3. Please identify any areas where water pools outside during rainy weather?                          
    4. Do you have difficulty opening and closing any of the doors and windows?   
    5. Do you hear any rattling noises related to doors, windows, roofs, etc during windy periods?   
    6. Do you have any cold air leakage in and around windows and/or doors?   
    7. Do you have any mould, mildew or other types of fungi growth on the floors, walls, ceilings    
    8. Is there any signage on the exterior of the building that interferes with maintenance?   
    9. Is there any significant repair/replacement work to the building enclosure that is scheduled to occur in the near future? If yes, please specify:
    10. Any general comments about the building enclosure?


    Risk Management
    Risk management is about identifying the undesirable things that could happen to the organization, to the people who live and work in the building(s) and the things that must be done to avoid (or to lessen) the negative impact.
    Some of the primary risks that are to be avoided or mitigated through management of the enclosure system are as follows:
    • Water damage to the building structure (wood frame or concrete)
    • Increased costs associated with collateral damage to the structure
    • Water damage to personal effects and finishes in the suites
    • Mould growth associated with water infiltration to wall cavities
    • Poor indoor air quality arising from mould growth in wall and floor finishes
    • Nuisance and frustration to residents of the building due to water leaks, poor indoor air quality and poor indoor space conditioning (heating and cooling).
    • Increased energy cost from loss of heat through walls and windows
    • Accelerated deterioration of some assets
    • Greater financial hardship through large special assessments and onerous demand loans
    Some of the hazards that can affect the performance of the electrical assets are as follows:
    • Water exposure
    • Vegetation accumulations in drains
    • Moss growth on roofs
    Once we fully understand and appreciate the significance of the consequences that may arise from inadequate care of the enclosure assets, we can start to make appropriate plans for operations and maintenance so as to mitigate the impact on our organization and our people.



    Operations
    Operations is about the day-to-day activities in the building that must be coordinated amongst different people with a variety of skills.  Listed below are some of the things that should be considered in estimating the level-of-effort to directly operate (or indirectly care for) the enclosure assets and the composition of the team that will be required.
    • Asset Durability & Service Life - The assets in the enclosure system are generally medium-life assets (such as roofs) and long-life assets long-life (such as cladding and glazing systems). There are also some short life assets (such as paint coatings and balcony membranes) with a 5-10 year life span.
    • The Asset Inventory - The typical building will have an inventory of approximately 25 building enclosure assets and each of these will require a different strategy for maintenance, repairs and renewals. The enclosure assets represent about 25% (one quarter) of the total asset inventory.
    • The Team – Work on the enclosure system requires a variety of different types of contractors with different skill levels. Some contractors will be required to use fall protection equipment (eg. window washing) and therefore should have adequate prior training in the use of specialized equipment.
    • Equipment & Supplies – Under normal operating conditions, there is no need for the organization to keep any equipment and supplies for the enclosure assets.
    • Documentation & Recordkeeping – The organization should keep its architectural drawings in a safe place. No recordkeeping is typically required for any of the enclosure assets other than the annual testing and certification of the fall protection anchors.
    Failure of the enclosure assets can present a number of risks to the organization. It is therefore important to put the right team in place to monitor and manage the assets.



    Maintenance
    Maintenance is work done to preserve the enclosure assets over their useful service lives, without unforeseen repairs or major renewal. Included below is a summary of the things to consider for ongoing maintenance and periodic repairs of the different components of the enclosure system. 

    Many of the enclosure assets do not lend themselves well to time-based maintenance strategies and are better suited to condition-based maintenance. Essentially this means that the frequency and scope of maintenance of the enclosure is dependent on exposure conditions and weather conditions. This makes it difficult to set up regular maintenance schedules (as in the case of the electrical and mechanical systems).  Included below is a few examples of maintenance activities on enclosure assets:


           Maintenance
    • Washing of the exterior inaccessible windows
    • Cleaning of the gutters and roof drains
    • Inspecting of the sealant for signs of distress
    • Testing of the fall protection anchors on the roof
    • Cleaning of the dryer vents
           Care
    • Do not drill holes exterior walls to hang Christmas lights and wind chimes.
    • Do not extinguish cigarette butts on balcony membrane.
    • do not drill holes into window frames for burglar bars and alarms.
    • Do not drag seasonal furniture across the balcony membrane.
    • Do not drip barbecue fat on the membrane.
    • Do not tear the balcony membrane when using shovels to clear ice and snow.
    • Installation of splashpads beneath RWLs
    • Installation of pavers/mats leading to rooftop HVAC equipment
    • Clearning pruning of trees as roof perimeter



    Repairs
    One of the most significant signs of distress in the enclosure system is water leaks into the building. Repairs to the enclosure system can be very expensive. Also, managers must be careful to steer clear of cheap solutions that will not last. Since the enclosure system is comprised of many layers, it is often difficult to trace the source of the problem and affect the correct repair. A specialist should be engaged for all enclosure repairs.



    Capital Planning
    Capital planning is about making appropriate financial preparations as each of the enclosure assets approaches the end of their respective service lives. As assets get beyond a certain age, maintenance is no longer sufficient to stop their physical deterioration (or slow down their obsolescence) and plans need to be made to replace and/or upgrade some (or all) of the components.

    The building enclosure system contains some of the most expensive assets that will ever need to be replaced. Typical projects include roof renewals (see figure below), balcony and deck membrane replacement, exterior re-cladding and re-glazing.


    Listed below are different types of capital projects in the enclosure system:
    • Cedar-to-Asphalt Shingle Roof
    • Acrylic-Dome-to Unit Skylights
    • Faceseal-to-Rainscreen Cladding
    • Liquid applied to sheet goods waterproofing retrofit

    Financial analyses of the systems can be found at:

    The capital load of the enclosure system generally overshadows all the other systems.



    Energy Management Considerations
    The enclosure system presents the most significant opportunities for improved energy efficiencies in buildings, such as the installation of new thermally improved windows. Since projects in the enclosure system are some of the most expensive that the building will ever face, occur infrequently and can have the most dramatic energy paybacks, they are sometimes referred to as “deep energy retrofits”. These types of deep retrofit projects can be undermined by a lack of a holistic approach to energy efficiency.

    For example, it may be advantageous to the organization to coordinate the replacement of walls and windows. It is important to recognize that improvements to the energy efficiency of the enclosure system can reduce the load requirements of the mechanical and electrical systems inside the building.  Energy modeling should therefore be done by a qualified consultant to guide the organization as to appropriate scope of work and review of the different energy efficiency options.
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    Fig. Windows and glazing systems are generally long-life assets and form part of the enclosure (envelope) system..


    Human physiology as an analogy to illustrate the importance of system interaction and comparing the enclosure system to the dermatological system.
    Fig. Human physiology as an analogy to illustrate the importance of system interaction and comparing the enclosure system to the dermatological system.



    Distribution of medium-life assets within each of the eight primary physical systems
    Fig. Distribution of short-life, medium-life and long-life assets within each of the eight primary physical systems.


    types of roofs
    Fig. Samples of different types of roofs, which are predominantly medium-life assets with service lives ranging from 20-30 years. The single exception is this set is the sloped metal roofs which are a long-life asset.


    The capital load distributed across the eight primary physical systems for different types of buildings
    Fig. The capital load distributed across the eight primary physical systems for different types of buildings.



    Some examples of long life assets within the building enclosure system
    Fig. Some examples of long life assets within the building enclosure system.


    ../Concepts/Implementation-strategies-assetinsights.JPG
    Fig. The 10-year tactical plan for a building that indicates the impact of the enclosure system on the capital load, which is significantly higher than the other systems.


    Cedar shingle roof retrofitted to asphalt shingle
    Fig. Cedar shingle roof retrofitted to asphalt shingle.


    1
    Fig. Wood siding is an example of one of the building enclosure assets, which falls into the walls sub-system. 


    Polyurethane roof (12 year life) replaced with upgraded SBS roof (20 year life).
    Fig. Polyurethane roof (12 year life) replaced with upgraded SBS roof (20 year life).


    Conceptual representation of the interconnected systems in buildings
    Fig. Conceptual representation of the interconnected systems in buildings.


    Seasonal maintenance program represented by system.
    Fig. Seasonal maintenance program represented by system. The building enclosure requires maintenance predominantly in the summer and fall seasons.

    See also:
    Compare with:





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