Management and Mitigation of Damages from Incidents in Facilities Owned or Leased by PSPC

(This document to be utilized in conjunction with the Infrastructure Continuity Plans) This link is available only to clients with access to The Source, the PWGSC/PSPC intranet.

An incident is an unforeseen event which is either planned or accidental in nature. The types of incidents vary and can include: structural collapse, electrical failure, flood, fire, personal injury etc. An incident claim is a process whereby an attempt is made to recover the costs of damages resulting from an incident and can be initiated either by or against Public Services and Procurement Canada (PSPC). Since PSPC does not self-insure, claims may only take place where there is a liable third party. Determination of liability must take place immediately following an incident.

In view of the large number, varied character and widespread locations of PSPC facilities, it is economically prudent for PSPC to underwrite its own risks. It has become federal policy not to utilize commercial insurance as a protection against risks to which the government alone is exposed. On the other hand, when PSPC engages contractors, the construction contract requires that the contractor provide insurance against all risks including those involving damage to the structure, third party personal injury or property damage. Every year PSPC must manage and mitigate incidents occurring in its facilities. These incidents can cause extensive damage to structures and can result in lengthy and costly lawsuits when issues such as liability, assessments and recovery of PSPC costs for losses and damages have not been adequately addressed.

PSPC gives high priority to minimizing disputes and to preventing, mitigating, and resolving claims in a timely fashion. In 1998, PSPC created the Claims Prevention and Management Unit (CPMU) to help achieve these goals. The Real Property Branch (RPB) is responsible for resolving disputes that arise on their projects. However, due to the technical complexity of many of today's claims, CPMU can provide clear, concise and timely advice to encourage swift and economical resolution of such incidents. To be most effective, the CPMU needs to be involved at an early stage of the incident.

Although it is not always possible to recover the costs of a incident, it is essential to document all salient information in order to be prepared in the case where insurance coverage is in place or negligence has been assigned to a non-governmental entity. ARCHIVED - TB Policy on claims and ex gratia payments clause 7.1 Investigations states: “As soon as a department becomes aware of an incident which could lead to a claim by or against the Crown or against a servant, it shall conduct an investigation of the incident at the earliest reasonable opportunity.” Cost recovery can take the form of a simple request or a more complicated litigation process. The issue of legal liability forms the essence of cost recovery. In cases where incidents occur in PSPC facilities, it is the responsibility of RPB to ensure that mitigation procedures are followed concerning health/safety, damages and losses to materials etc., and that all measures are taken at the appropriate times to recover damages where liability is demonstrable. Prompt notification to senior management is necessary in order that communiqués may be issued to the affected groups.

Project or property and facility managers must ensure that all PSPC discipline expertise (health and safety, legal, contractual, environmental, architectural, mechanical, electrical, claims, etc.) form part of the project team and will engage private sector insurance claims adjusters as warranted to act as advisors for the incident damage cost recovery process. The advice of Justice Canada Legal Counsel is required for any claim over $25,000 and should form part of the investigation and cost recovery team. In cases of privately owned facilities, ensure that the owner adheres to the terms and conditions of their contract as it relates to incident management and restoration, and that due diligence is exercised.

Helpful Hints for Incident Management

Incident Management Activities - Do's and Do not's

Mitigate:Stop the cause/limit damages/ensure safety of personnel. What you do in the first hour is critical. Project manager must take charge (in leased buildings, the landlord must also be involved)

  • Do: Take immediate action. Assume existence of health hazards/extensive damages. Advise stakeholders.
  • Do not: Assume it will be taken care of by others.

Plan and organize: Research what will need to be done, with appropriate expertise. Treat as a project. Determine and retain evidence as to the cause of the incident and liability. If there is insurance coverage, hire an insurance adjuster and work with their input.

  • Do: Plan with management, Legal Services, Claims Prevention and Management Unit and users without delay. Obtain expertise and refer to procedural documents.
  • Do not: Assume that people will know what to do. It may be their first time dealing with an incident.

Restore: Implement/monitor the restoration project which must have a defined, itemized scope of work (work breakdown structure) with fixed start and finish dates. Consider loss mitigation, coordination procedures and completion.

  • Do: Strive to restore pre-incident conditions or ensure that adequate compensation is obtained. Determine the reimbursing party.
  • Do not: Assume things will be taken care of by others.

Close out the restoration: Obtain certifications of compliance with predetermined goals.

  • Do: Arrange for final inspection certifications, releases, including implementing completion procedures
  • Do not: Let the project "die out". Something will come back to haunt you.

Recover costs of damages: Remain committed to the recovery of monies - as this will prove challenging.

  • Do: Document all costs (including labour) and retain copies of paid invoices. Follow through with legal action if necessary.
  • Do not: Assume others will action. Detailed documentation is critical for cost recovery.

Microbial Remediation Procedures

(Example for Buildings Projects)


The purpose of this procedure on microbial remediation is to clearly outline the appropriate action that should be taken to eliminate microbial contamination and minimize risk of exposure.


Microbials; fungi, moulds and yeast, bacteria, and viruses are commonly found in both outdoor and indoor environments. They are a natural component of our world and are found on plants and leaves, in air, soil and water, on dust and even in our body. There are numerous microbial species and although there are no regulated exposure values or thresholds, certain microbials can cause adverse health effects such as eye, nose and throat irritation, allergic or asthmatic reactions, hypersensitivity, disease (Legionella bacteria), infection (Aspergillus), and other specific and nonspecific health symptoms. While there are no "threshold limit values" or TLVs for microbial exposure, there are established numerical and qualitative interpretative guidelines. Individual susceptibilities vary, however occupants who have a suppressed or weakened immune system (those taking steroids, having AIDS, undergoing chemotherapy or radiation, with asthma, severe allergies, or other chronic inflammatory lung diseases have a greater risk of exposure.

The first principle of microbial control is that mould should not grow indoors. These "amplification" sites occur when there is sustained wet or damp conditions. Rapid response and proper corrective action to water damage (floods and leaks) will likely avoid microbial contamination. However, there are instances where mould growth will occur and remediation procedures outlined in this document will reduce the extent of damage, cost, and risk of exposure.

Operating Strategies to Limit Microbial Growth

In addition to following the "Remedial Procedures for Water Damage in Buildings", when accidents occur, there are several proactive operating strategies to limit microbial growth within a facility:

  • Reduce outdoor microbial quantities by filtering the air supplied by the mechanical system. In a large office building with a central mechanical system, 85% dust-spot efficiency filters are standard. Smaller facilities (1 – 2 stories), with rooftop units usually have 30% pleated filters.
  • Maintain relative humidity levels below 60%. There may be special areas requiring higher humidities, however at no time should there be condensation or wet surfaces in these or any other locations.
  • Within the central HVAC system and facility air-handling system (compartmental, fan-coil and induction units), there should be no wet insulation or stagnant water. Condensate pans should not be internally lined with porous insulation – this is an ideal breeding site for microbials. Avoid humidifier spray past the drift eliminator. Steam systems should have 100% evaporation.
  • Reservoirs under water-spray humidifiers, condensate pans, and other places where water is present must be rigorously cleaned and maintained according to a schedule and protocol. [For example; it is normal to clean a reservoir under an operating cooling coil on a monthly basis; brushing all surfaces with bleach and rinsing. Fan-coil condensate pans should be similarly cleaned annually.]
  • Avoid condensation on cold surfaces or "thermal bridges", such as windows and sills, ducts, pipes, etc. Either these places must be better insulated (increasing the dew point) or relative humidity levels must be lowered.
  • Eliminate the potential for sustained wet areas such walls behind sinks without proper splash guards, carpeting under water fountains, floor and baseboard cracks, ceilings under leaks, etc. Any wet surface will become contaminated over time.
  • Ensure maintenance and preventive maintenance procedures and good housekeeping for the mechanical system, the air supply ducts, the return and exhaust systems, and within the building (induction/convection/fan-coil units, VAV boxes, etc.) are in place. Compliance should be reviewed and an activity log kept.

Analysis and Interpretation:

Visual inspection can identify possible microbial contamination. Damp or wet areas, stained surfaces, discolouration, and musty odours can be potential growth areas. Locations of recent flooding or water damage are also suspect, and the use of a moisture meter can establish areas of unseen problems behind walls or under floor covering. Measurement of microbials is in colony-forming-units (CFU); airborne is CFU/m3 and surface is by square area of visible mould, or by CFU/ on a glass slide, agar strip or dish, on a tape, or on a contact plate. Another measurement method is to count CFU/ per gram of dust. Collection methods and assays are beyond the scope of this remediation guideline. There are established protocols that should be followed to assess airborne, surface and bulk samples. When microbial species and levels need to be established, a professional experienced in sampling and interpreting lab results should be retained.

Remedial Action:

Universal precautions are used with the assumption that an exposure hazard exists, whether it actually does or not, unless proven otherwise. While very few microbials are toxigenic (can produce a compound, a mycotoxin, harmful to humans), or pathogenic (can cause disease), sensitivity and allergic reactions can occur in persons exposed to a single heavy exposure of common microbial species. Therefore the use of respiratory protection, gloves and eye protection is recommended. [Note: bird and bat droppings are pathogenic and specials precautions apply.]

The visual presence of mould on materials or on building surfaces does not mean that spores or fungal byproducts are airborne. Exposure to mould can be by inhalation, physical contact, or by ingestion. However because measurement methods vary, identification of non-toxigenic and toxigenic species takes several weeks, and susceptibility and health effects are largely unknown, caution should be exercised in removal (remediation) of mouldy areas. This applies not only to the person doing the task, but to the entire process; the prime directive being that remediation work must not expose building occupants to any microbials i.e., the goal of remediation is to remove or clean contaminated materials using proper work practices and isolation techniques so as to not spread contaminants.

Excessive contamination, particularly if heating, ventilating, and air-conditioning (HVAC) systems or large indoor spaces are involved, should be assessed by an experienced health and safety professional and remediated by personnel with training and experience handling environmentally contaminated materials. Lesser areas of contamination can usually be remediated by trained in-house maintenance personnel.

Mouldy materials when bagged and removed from the facility can be placed in a regular garbage bin; there is no need for special (hazardous waste) disposal. There are four levels of microbial remediation, determined by the size of the contaminated area. There is also a separate category for HVAC system remediation.

Following an expert panel document known as "The New York City, Guidelines on Remediation of Fungi", 2000.

Level I: Small Isolated Area (less than 10 square feet, or 1 m2 )

  • Remediation by trained building maintenance staff. Respiratory protection required, either a proper face mask, N95 disposable or better. Use gloves and eye protection.
  • The work area should be unoccupied.
  • Wash all hard, non-porous surfaces with a detergent and dry or use a 5-10% bleach solution. As bleach will leave a residue, rinse and dry after 15 minutes.
  • Discard soiled or wet ceiling tiles, drywall, or wet insulation. This should be double bagged and sealed within the work area.
  • Fleecy materials such as upholstered chairs, partitions, drapes, etc. that cannot be removed and professionally cleaned should be discarded.
  • Vacuum surrounding areas with a HEPA (high efficiency particulate air) filtered unit. Hand wipe ledges and areas not vacuumed. Clean floor.

Level II: Mid-Sized Area (1 to 3 m2). Same procedure as Level I, plus:

  • The work area should be covered with a plastic sheet and sealed with tape to contain dust and debris. If dust will be generated, mist the surface before task.
  • After the job is complete, mop the hallway from the site to the exit.

Level III: Large Isolated Area (3 to 10 m2 ). Same procedure as Level II, plus:

  • A dedicated project or asset and facility manager should oversee job, and use trained personnel or contractors familiar with mould abatement. Use disposable protective clothing, HEPA filtered respirator, and eye protection.
  • Cover the work area and the adjacent areas to contain dust and debris. Isolate adjacent areas and restrict access by use of a slit entry and covering flap.
  • Air supply systems and exhausts; diffusers, grills, induction and convection units, etc. should be sealed with plastic sheeting. If ventilation is required, insure that the space is under negative pressure; that is, air flows from adjacent clean areas to the contaminated space.
  • Cleaned items and equipment left in place must be sealed until the remediation process is completed.
  • All items and work equipment must be cleaned before removal from the remediated area. Care should be taken with final removal of the barrier and plastic sheeting to minimize dust generation; fold to enclose the exposed side and discard.
  • If remediation process is expected to generate a lot of dust from abrasive cleaning of contaminated surfaces or from demolition of walls and ceilings, or if the visible contamination is heavy (not patchy), then level IV procedures should be followed.

Level IV: Extensive Contamination (greater than 10 m2 in area):

  • The work area should be placed under negative pressure. A negative air machine, with a HEPA-filtered exhaust, or a window-mounted unit can be used. Ideally the negative air machine is exhausted outdoors.
  • Contamination hazard and restricted entry signs must be posted at all entry points. Double layers of polyethylene should be used on a wood/metal frame to create a barrier.
  • Airlocks and a decontamination room must be provided as well as a separate nearby washing/showering facility. Place waste container in decontamination room for contaminated clothing.
  • Personnel entering the remediation area must wear a full-face respirator with HEPA cartridges or a powered air purifying respirator, disposable protective clothing covering both head and shoes, and gloves. Respirators should be left on until outside the decontamination chamber.
  • Contaminated materials that cannot be cleaned should be removed from the building in sealed plastic bags or covered containers. The outside of the bag or container should be cleaned with a damp cloth and a detergent solution or HEPA vacuumed in the decontamination area prior to removal.
  • A communication plan should be implemented. Ideally, this plan is already written and will include a single point of contact, hazard communication to the Health Canada, management, staff and unions, occupational safety and health committees, etc. Full disclosure of plans and results, having a team approach, and seeking expert advice and assistance are effective communication mechanisms.
  • It is prudent to vacate occupants from adjacent areas during the remediation process.
  • Air monitoring should be conducted prior to occupancy to determine if the area is fit to reoccupy. Compliance with Health Canada/PSPC indoor air quality (IAQ) guidelines should be demonstrated.

Remediation of the HVAC System

Small areas, under 1 square meter (10 square feet), can follow the following procedure:

  • Remediation can be conducted by regular maintenance staff or contractors trained on proper removal and containment methods, personal protection, and potential health hazards.
  • Respiratory protection (N95 disposable mask or better), gloves and eye protection should be worn.
  • The HVAC system should be shut down and supply ducts (if not contaminated) should be sealed.
  • Avoid the migration of dust and debris from the work site to non-contaminated adjacent areas. Isolate the zone, cover clean components, and vacuum the site after the task has been completed. Clean filters can be removed before remediation inside the air-handling unit; reinstall before startup.
  • All contaminated materials should be cleaned or removed. Surface dust can be removed by HEPA vacuuming. Heavily contaminated hard, non-porous surfaces, should be first sprayed or wiped with a disinfectant (usually 5 – 10% bleach solution). The surface should remain wet for at least 15 minutes, before wiping and drying. Porous materials must be discarded; seal in plastic bags.
  • Clean exposed components such as fans, coils, pans and reservoirs using bleach, then rinse and dry. Motors, bearings, sensors, electrical components, etc. should be protected
  • Do not transport contaminated materials through occupied spaces. If this is not feasible, then bags and containers must be first washed or vacuumed in a decontamination chamber.
  • All tools and equipment used in the decontamination process must be cleaned prior to removal from the work site.

Larger contaminated areas within the HVAC system or in the mechanical room should follow the following additional steps:

  • Isolate the contaminated area and place under negative pressure. Restrict access and post hazardous materials sign at entry points. Provide air locks and a decontamination room, washing, and cleanup facilities.
  • A full-face respirator with HEPA cartridges or a powered air purifying respirator, disposable clothing with head and foot covering, gloves and eye protection must be worn.


The potential for microbial contamination exists in every building and within every HVAC system. The two basic requirements for microbial growth are first, a moisture source, and second, a nutrient. Fungal spores and bacteria are prevalent outdoors and indoors and so are nutrients such as dust and soil. Therefore control of moisture and good housekeeping will reduce the possibility for microbial growth. Given the right conditions, microbials will grow on any surface. A rapid response to water damage using established remediation procedures will prevent microbial contamination.

If microbial growth does occur; containment, cleaning and removal of contaminated materials must proceed to reduce the risk of exposure and to avoid further deterioration. During this process, procedures must be in place so that occupant exposure is not increased. This is the first principle of remediation.

There may be microbial contamination and remediation issues that are unique; where no guidelines exist. This document is intended to provide knowledge and a methodology to proceed towards an informed resolution – one which minimizes the risk to safety and health.

Remedial Procedures for Water Damage

(Example for Buildings Projects)


Within the life-cycle of a facility, water damage due to plumbing leaks, flooding, major spills, sewer back-ups, etc. can occur. Water damaged building materials, interior furnishings, and structural components, if not appropriately managed, can become significant sources of microbial (bacterial and fungal) contamination. Exposure to these contaminants can lead to potential health problems ranging from simple irritation, allergic responses, environmental sensitivity, to infection. Depending on the source, extent, and location of water intrusion, there are various cleanup and remedial procedures to effectively control the situation and minimize damage, microbial growth, and health risk.

There are many variables to consider when water damage occurs, however, the primary goal is to dry wet materials as quickly as possible in order to limit damages. Microbials are found in both the outdoor and indoor environment and growth will occur when moisture is present. As it is impossible to eliminate mould spores indoors, it is important to prevent moisture problems within a facility and remediate water damage before microbials can grow. The remediation of a water-damaged area must also be done under both "universal precautions" and "controlled conditions". Water quality must also be considered in the remediation process.

Universal precautions are used with the assumption that a hazard exists, whether it actually does or not, unless proven otherwise. Therefore, workers must use protective measures until the hazard is proven not to exist. These measures incorporate personal protection: appropriate respiratory and eye protection, gloves, boots, and disposable coveralls and include:

  • a mask rated for toxic dust or a respirator with HEPA (high efficiency particulate air) filter cartridges must be worn. (Dust masks do not provide adequate protection against microbial contaminants).
  • full-face respirators or goggles must be designed to prevent the entry of dust and small particles. Safety glasses or goggles with open vents are not acceptable.
  • hard hats and safety shoes may also be required.
  • good housekeeping and personal hygiene practices should be implemented.

Controlled conditions require isolation or containment of the affected areas to prevent the dispersion of possible contaminants to other sections of the building and consist of the following steps:

  • place the work area under "negative pressure" to ensure that air flow is from the clean surrounding area to the area undergoing remediation using negative air machines, fans or exhaust systems.
  • minimize damage by covering or removing items not yet soiled.
  • remove debris and wet materials with care; bag and seal materials, cover garbage containers, and provide drop-cloths and coverings from the work area to the exit. These materials can be discarded as ordinary construction waste. All equipment used inside the remediation zone must be cleaned before removal.

Water Quality:

Table Summary

This table lists water categories and their sources.

Water quality categories are determined by the 'source' not by the actual colour of the water
Water Category Source
Clean Water
Broken water supply lines, sprinklers, steam leaks, sink overflows, broken toilet tanks/bowls that do not contain contaminants, melting ice and snow, rainwater, and fire-fighting efforts
Grey Water
Toilet overflows containing urine, discharges from washing machines and dishwashers, and from sump pits or wells (carried microorganisms i.e. bacteria, fungi, parasite, and virus, and it a potential exposure hazard if left untreated)
Black Water
Sewage, broken water traps and flooding from outdoor sources

All water, including "clean water" can result in the proliferation of bacteria and fungi in building substrates and contents. The materials that are most susceptible to microbial contamination are those which are porous, such as wallboard (drywall and gypsum), insulation, ceiling tiles, carpets, and textiles. As time lapses, wet materials become progressively contaminated and it is therefore critical to start the remediation process within 24 hours of the time of damage. As the quality of the water deteriorates, greater damage to the building and contents, along with increased environmental hazards are likely to develop. Therefore a rapid response and remediation plan must be fully supported and implemented as soon as water damage occurs.

Remediation Program

The extent and methods for remediation of water-damaged materials and structural components are dependent on many factors; water type (quality), amount of water intrusion (quantity), area of damage (size), material porosity and composition, and time left untreated. A water damage remediation program incorporates the following:

  • Evaluation of safety aspects such as structural integrity, potential for electrical shock hazards, gas leaks, and exposure to toxic gases and biohazards before entering the water-damaged area.
  • Assurance that persons doing remediation for "grey" or "black" unsanitary water damage, are equipped with personal protective equipment (PPE), including, but not limited to
    • respirator equipped with HEPA and organic vapour cartridges,
    • rubber gloves,
    • eye protection,
    • protective suit, and rubber boots.
  • Assurance that individuals not immunized against tetanus, those with health problems such as asthma, allergies or respiratory disease, with skin cuts or abrasions, and those with a suppressed immune system, are not present or working in this area.
  • Immediate action to:
    • isolate the damaged area, post barriers and warning signs and relocate occupant,
    • locate, eliminate, repair/contain the source of the water intrusion as much as possible,
    • move or protect equipment/furnishings against further damage and contamination
    • seal perimeter air-handling units, exhaust systems, and return plenums,
    • remove initial water by extraction or absorption using mops, towels, squeegees, pumps, wet-vacuums or other water extraction equipment,
    • dry the damaged materials by wiping or vacuuming, using fans and heaters, dehumidifiers, and by running the HVAC system to ventilate and exhaust humid air. Dehumidifiers are more effective than ventilation in warm weather. Windows may be opened if outdoor conditions are favorable to assist the drying process.
    • remediate water-damaged structural components, furnishings, equipment and the mechanical (HVAC) system to avoid microbial contamination.

Remediation of Materials

Listed below are the recommended remediation procedures for various materials exposed to either clean water or to contaminated gray or black water. Remember that a rapid response, within 24 hours, is critical in minimizing the risk of contamination and reducing damage. In most instances, porous materials that have been exposed to black water (sewage), must be discarded.

Wet vacuum to remove excess water and wet debris and use a HEPA-filtered vacuum to clean dry materials. High efficiency filtration will ensure that spores are collected and not dispersed. Dispose of the contents in well-sealed plastic bags.

Note that the use of disinfectants or biocides (containing chlorine, bleach, peroxides, ammonia, formaldehyde, and other chemicals) are not generally recommended for cleaning hard, non-porous materials. Most disinfectants contain respiratory irritants and must remain on the surface for 15 minutes or longer to be effective against microbial growth. The use of a scent-free detergent is usually effective (scented cleaners may be objectionable to some). When a disinfected is used, it can be wiped or sprayed on but never misted, to avoid an inhalation hazard. Always use disinfectants in a well ventilated area. Follow instructions on the label. All products used should be accompanied by their Material Safety Data Sheets (MSDS).

Note: Liquid chlorine bleach (sodium hypochlorite) or bleach, is commonly used as a disinfectant and concentrations can vary from a 5% household solution to 10% industrial strength. However, it can stain certain textiles and does leave a residue which can be rinsed or wiped off. If the residue is not an appearance issue, such as in the mechanical room, then leave it on. Never mix bleach with ammonia as this will produce toxic fumes. For wooden surfaces which could be damaged by bleach, a 5 to 10% borax solution can be mixed with dishwashing detergent.

Hard surfaces such as metal filing cabinets, desks, bookcases, wood furnishings, etc., need to be wiped with water and detergent and dried completely. Mops, sponges or cloths must be kept clean so that no residual soiling remains on any exposed or hidden surface.

Furniture made of solid wood, or veneered and having intact laminates, should be dried and cleaned. Particle board or pressed wafer board furniture exposed to clean water can also be dried and cleaned, but should be monitored for subsequent microbial growth or odours. If this becomes evident, discard the furniture. Delaminated items should also be discarded.

Doors that have become wet can be cleaned and placing them on a level surface between wooden strips will facilitate drying and prevent warping. The exception is hollow doors where gray or black water has penetrated; these should be discarded. Remove, clean, and disinfect all doorknobs and locks. Sliding windows and doors should be removed so that both the unit and the track can be cleaned and disinfected. Clean and dry when items are exposed to clean water; clean and disinfect for gray and black water damage.

Upholstered furniture that has become wet with clean water should be dried within 24 hours and monitored for fungal growth and odours. Discard upholstered furniture and other highly absorbent stuffed fabrics such as wall partitions, when they become saturated with gray or black water. It may be cost effective to remove the upholstery from furniture and clean the wood or metal frame.

Carpets that have become wet with clean water (or gray water over a small surface area) are remediated by the following steps :

  • Remove all materials (desks, furnishings, cabinets) from the carpet.
  • Extract as much water as possible from the carpet using wet vacuums.
  • Shampoo the carpet with a dilute surfactant.
  • Soak with a 10% bleach/water solution. (A biocide is not recommended)
  • Rinse and extract the carpet with clean water to remove detergent/bleach residues
  • Instead of soaking with bleach and rinsing, the carpet can be steam cleaned. Water is heated above the boiling point and the moisture is vacuum extracted.
  • Dry the carpet immediately after treatment. Increase the temperature, use heaters, fans, and dehumidifiers to accelerate the drying process. During the summer, it may be more difficult to dry the carpet if conditions of high relative humidity exist. If the carpet cannot be dried, it must be discarded.
  • Verify that the carpet, the under-padding, and the floor are dry. A section may have to be lifted or a moisture meter can be used. If the underlay or floor is wet, the carpet should be removed to facilitate drying. If the carpet is glued directly to the floor, investigate and monitor subfloor for moisture and damage. Swelling, buckling, ripples and cracks in the subfloor will require removal of the carpet and underlay.
  • Vacuum the carpet. Fine particulates will pick up the fibers during the drying process. Use an industrial grade vacuum with a beater bar.

If visible mould appears or the area smells of mould, the treatment process (cleaning and bleaching) should be repeated. This should be done only once. If complaints, mould growth, and odours persist, the carpet and underlay will have to be removed under controlled conditions.

Carpets and under-padding saturated by black water must be discarded. The exception is when a small (1 square meter or 10 square feet) area is affected and the above procedures can be followed, or if the carpet is an area rug which can be removed and sent for professional cleaning. Note that carpets and under-padding are made of various natural and synthetic materials, each having different water retention and drying properties, and cleaning requirements. However, in all cases, the carpet must be completely dry within 24 hours after treatment.

Textiles that have been water damaged should be promptly laundered in hot water and dried in a dryer, or sent to a dry cleaner.

Books, files and papers made wet by clean water can be air dried. Non-essential items should be discarded. If possible, photocopy essential papers after they have dried and discard the originals. If you cannot tend to the papers promptly within 48 hours, then they can be wrapped in plastic bags or in wax paper and frozen until later. Books and files damaged by gray water can be rinsed, blotted dry, then air dried or frozen. A process of "vacuum freeze-drying" can be used in which controlled heat and vacuum pressure is applied to frozen materials such that moisture is changed directly from a frozen state to a vapour and extracted. HEPA vacuum any residue/debris/dust off of all surfaces after drying.

Photographs can be rinsed in cool clean water and air dried. Do not touch surfaces.

Dishes, cutlery and utensils should be thoroughly washed and then either placed in a dishwasher or sterilized in boiling water or in a disinfecting solution for ten minutes.

Remediation of Structural Components

It is important that building materials be allowed to dry. Some materials such as drywall covered with vinyl wallpaper or with wood paneling, will act as vapour barriers and impede drying. In time, this can result in hidden mould. Therefore during the remediation process, it may be necessary to access hidden areas such as wall and ceiling cavities, crawl spaces, and shafts to investigate extent of water damage.

Ceiling tiles – remove and dispose of all wet ceiling tiles within 24 – 48 hours of water damage. The only exception would be if 1 to 3 tiles had become wet due to a small steam or clean water leak and the shape of the tiles were not altered or discoloured. In this case the tiles can be air-dried and reused.

Drywall and insulation that has been water damaged should be removed within 24 hours. A moisture meter should be used to identify the extent of water damage; cut drywall at least 30 centimeters (12 inches) above the moisture mark. Wet fiberglass, mineral wool and cellulose lose their insulation properties and tends to compress or mat. Any insulation that remains wet will provide an ideal substrate for microbial growth. Foam insulation can be decontaminated by cleaning and drying; after cleaning, a bleach solution can be sprayed on and left in place. If water has penetrated the insulation, the insulation should be removed.

Lathe and plaster that has become wet with clean water should be dried within 24 hours. Minerals from the wall may leach and form a chalky surface. This loose material will need to be removed under controlled conditions and the surface allowed to dry. Lathe and plaster exposed to gray and black water must be evaluated for physical damage and degree of contamination. If water has penetrated the material, removal is warranted. If a small surface area has been affected, cleaning using a disinfectant or biocide is recommended. If the plaster/lathe develops a strong odour, with or without visible mould growth, the water-damaged area should be replaced under controlled conditions.

Wall paneling made from wood laminates or vinyl can be cleaned and dried. Particle or wafer board that has been saturated with black water should be discarded. Damaged, stained, or swollen walls should be replaced. In general, walls that were under water should be stripped to the studs 30 cm. above the flood line. The wall cavity should be checked for water damage; insulation, outer walls, beams, etc. The ceiling below a flooded floor should be opened and inspected; if wet, it must be remediated.

Concrete floors (and walls), decking, and other sub-floor materials react differently to water damage according to their porosity. In all cases prompt cleaning, drying, and evaluation is necessary. When cleaned using a detergent, rinsed with bleach, and dried are not usually susceptible to microbial growth. If contaminated with black water, cleaning with tri-sodium phosphate (TSP) is recommended; all surfaces must be covered with TSP.

Vinyl, laminate, and hardwood floors are usually non-porous and can be cleaned and dried. Remove dirt between cracks. It should be verified that water has not seeped underneath the seams, along the walls, or under moldings.

Subfloors, padding and cushioning materials must be allowed to dry if damaged by clean water. Moisture intrusion can be verified by removal of a small top-floor section or by using a moisture meter. Often the top surface (carpet) appears to be dry while the underneath surface may be wet. It would be necessary to remove the top covering, and any wet under-padding, to achieve drying of all surfaces. If gray or black water saturates the porous subfloor layer, it must be removed and discarded. Plywood and particleboard subfloors saturated by water are usually not salvageable.

Remediation of Mechanical & Other Systems

Mechanical systems that have been flooded by gray or black water should be shut down to avoid the transmission of contaminants to other areas of the building. When cleaning system components, protect motors, bearings, belt drive assemblies, filters, ducts, and other non-damaged items from water intrusion. Vacuum clean the entire internal space of the HVAC system, including all components, supports, frames, mounts, etc. to remove loose dirt and debris. Hand scrub to remove residual dirt. Pressure wash other hard to clean system components. There should be no standing water or wet surface within the system after all components have been cleaned.

Wet fiberglass or other wet porous insulation in the air handling system (including supply ducts), should be discarded. Dry lining with an intact, undamaged barrier can be left in place. It is possible to clean these surfaces if they have been contaminated by clean water, using air pressure, brushes, and vacuum suction. However, the process must not degrade the lining or barrier. Note that the purpose of insulation can be for thermal or acoustic reasons and it may be advantageous to replace damaged porous insulation with closed cell foam type, and to place insulation on the exterior rather than the interior surface.

Filters that have become wet should be replaced. Undamaged filters can be removed and stored during system remediation. However at no time should the filters not be in place when the system is in operation.

Hard surfaces can be cleaned with a detergent or a bleach solution by hand wiping, or with a spray/pressure washer, wipe clean or vacuum.

Heating and cooling coils exposed to water damage should be cleaned using a pressure washer and cleaning agent at both the upstream and downstream faces.

Floor drains and sumps should be cleaned, disinfected and flushed. During a flood, the water pressure in plumbing systems can reverse, and water in hot and cold pipes can be contaminated with flood water. A plumber must inject bleach into the lines to disinfect them

Air supply and exhaust ducts that have been damaged with clean water will need to be inspected. Clean ducts may not pose a problem when they are dried. If water and dirt is visible, the entire affected system, including vertical sections, should be cleaned. If the system has been penetrated with gray or black water ducts will have to be decontaminated. [As it may be necessary to disassemble the system, it may be cost effective to replace the duct work.] It is not advisable to apply biocides or sealants on dirty surfaces. External duct and system insulation and wrapping that can be dried, can remain in-place. Verify that the insulation is dry throughout its entire depth and monitor for microbial growth. Water-logged areas must be removed and replaced.

Air-handling units along the perimeter of the building or within the ceiling plenum, that have been exposed to moisture must be reconditioned. Remove all fiberglass lining and filters. If damaged by clean or gray water, use detergent to clean surfaces by either hand wiping or by using a pressure washer. Do not get surrounding areas wet and vacuum after spraying. It may be best to clean removable components off-site. Coils and fins can be cleaned by a pressure washer or by a HEPA-filtered vacuum. Air-handling units contaminated by black water should be reconditioned or removed for decontamination off-site. A 10% bleach solution should be used to clean all surfaces. Fins and coils must be pressure washed. All porous materials must be discarded.

Registers, grills and diffusers exposed to clean or gray water should be wiped clean and dried. Items exposed to black water should be removed and disinfected before reinstallation.

Before the HVAC system in put back into operation a final purge is recommended. All supply air diffusers and air-handling unit grills should be covered with 30% or greater efficiency filter media. Tape to eliminate air leakage. Start system and run at variable speeds to dislodge dirt and debris for at least one hour. Remove all filter media, vacuum and clean any locations if necessary. Finally, the HVAC system may require testing, adjusting and balancing.

Electrical appliances, and other unique specialized components require inspection and repair by a qualified person. An electrician should turn off the power in the flooded area at the service panel before electrical appliances are removed.

Electric circuit breakers and fuses that were wet should be replaced. Switches and outlets that were under water can be cleaned and reused if still functional. Electric motors and appliances need to be cleaned, dried, and inspected. All water damaged light fixtures need to be opened, cleaned, dried and checked before being put back in service.

Computers, radios, and televisions which have been water damaged may be unsalvageable. Items soaked in black water should be discarded. Disks and CDs can be washed in clean, distilled water and dried with lint-free towels.


Water damaged materials, structural components, and mechanical systems can be remediated using established techniques and sound principles. However it should be recognized that there are occasional events that will require a unique resolution; one that is outside the scope of these guidelines. Hopefully, the ideas presented in this publication will positively influence the outcome.

While the remedial work is intended to be done using resources readily available either in-house or under contract, there are specialized expertise that can be utilized to advantage. For example, a person trained in moisture measurements (hydrographic mapping) can accurately indicate where hidden moisture lies and how much area has to be removed. Professional water damage, recovery, and restoration firms have specialized equipment (desiccant dehumidifiers, heaters, fans, etc.) and skills to manage flood remediation projects. Medium to large jobs may require a manager and a remedial action plan.

Microbial contamination does not need to follow water damage. A rapid response to contain and limit water damage, and the removal, cleaning and drying of contaminated or wet materials, will provide limited opportunity for microbial growth.

Post cleanup inspection and clearance sampling by a trained indoor air quality or environmental health professional are useful to ensure that the affected space is within established health and safety standards and guidelines. Microbial sampling may be required before final assurance is given (compliance testing). A pre-occupancy evaluation of the remediation effectiveness is warranted and prudent.

Finally, because of actual and perceived health risks, open and frequent communication with all concerned building constituents through a single, informed contact person is recommended.

Table Summary

This table lists remediation techniques for various materials.

Table 1: Remediation of Materials
Material Clean Water Grey Water Black Water
Hard Surfaces Clean and dry Clean with detergent or bleach and dry
  • Solid Wood
  • Particle Board, laminates
  • Upholstered

Clean and dry

Intact: clean and dry
Damaged: discard
Dry within 24 hours

If odours persist after cleaning, discard If saturated, discard


Carpets Extract water, shampoo. Soak with bleach, rinse, dry or, steam clean, dry Discard if area > 1 sq. Meter Area rugs can be sent out for cleaning
Under-padding Dry; removal of carpet may be necessary Discard
Textiles Laundry or dry clean Dry clean or discard
Books, Files, Papers Air or freeze dry, vacuum Photocopy or freeze dry, vacuum
Photographs Rinse in cool clean water, air dry
Dishes, Cutlery, Utensils Place in dishwasher or autoclave
Table Summary

This table lists remediation techniques for various structural components.

Table 2: Remediation of Structural Components
Material Clean Water Grey Water Black Water
Ceiling Tiles 1 - 3 tiles, dry Discard
Drywall/Insulation Remove saturated section and discard
Lathe & Plaster Clean and dry Disinfect small area, remove if saturated or odorous
Wall Paneling Clean and dry Discard
Concrete Clean and dry Clean with TSP
Vinyl, Laminate, Hardwood Floors Clean and dry. Inspect under holdings and floor
Sub-flooring Materials Dry Discard
Table Summary

This table lists remediation techniques for various mechanical components.

Table 3: Remediation of Mechanical Components
Material Clean Water Grey Water Black Water
Fiberglass Discard if wet or wetted
Thermal/Acoustic Lining Clean Discard
Hard Surfaces Clean with detergent or bleach
Coils Pressure wash both sides
Drains & Sumps Clean, disinfect, and flush
Water Pipes Flush with bleach
Air Ducts Inspect Disassemble and decontaminate or replace


  • Alberta Transportation and Utilities. 1998. Flood Disaster Detailed Information About
  • What to do Before, During and After Flooding, Alberta: Alberta Transportation and Utilities Disaster Services Branch.
  • Carlson N., and Quraishi A. assessed 1998. Managing Water Infiltration Into Buildings. Minnesota: University of MinnesotaThe WWW icon indicates a link that takes you outside the federal government's common web environment..
  • EPA. 200The WWW icon indicates a link that takes you outside the federal government's common web environment.. Mold Remediation in Schools and Commercial Buildings, Washington, DC: United States Environmental Protection Agency.
  • IICRC S500The WWW icon indicates a link that takes you outside the federal government's common web environment.. 1999. Standard and Reference Guide for Professional Water Damage Restoration, Vancouver, Washington: Institute of Inspecting Cleaning and Restoration Certification.
  • NYC DOH. 2000. Guidelines on Assessment and Remediation of Fungi in Indoor Environments, New York City: New York City Department of Health.

Forms, samples and checklists