Moist conditions under the sub-floor are expected after a flood, particularly one of long duration. However, a well drained and vented sub-floor should slowly but surely dry out. The time to dry out is very variable, depending on ventilation rate, soil type and design factors. If the subfloor has not dried out within 2-12 weeks then there may be additional problems restricting drying. Such problems may include

The persistence of high sub-floor moisture can result in significant deterioration of floor and its supports including fungal and mould growth on timber, corrosion of connectors, corrosion of steel work as well as a persistence of warping of floorboards, etc.

Poor sub-floor ventilation

The building code of Australia recommends that for timber clad houses there should be a minimum of 350 mm between the ground and floor joists. This should provide all the ventilation required as long as air movement across the sub-floor is not restricted. After a flood remove barge boards and other obstructions to air flow. Soil may have built up against the barge boards, this should be removed. Ensure that the sub-floor can drain away from the house. Also ensure that there are no-obstructions to air flow under the house. Flood debris or materials stored under the house may obstruct air flow. More seriously structural members such as concrete or brick walls may block airflow. Strategic vents should be placed in these members (at least 15600 mm2 per metre). If the sub-floor does not dry out and the separation of ground floor joist is significantly less than 350 mm it may be necessary to lower the ground level. Alternatively forced venting or as a last resort venting into living spaces may be required.

Sub-floor moisture traps

Moisture may be trapped at various points in the sub-floor. Earth may build up arround the perimeter of the house (particularly in old houses) so the sub-floor is effectively dammed.

Alternatively, hollows may be associated with stumps/piers or chimneys. These hollows may form during the flood itself or may be left from the building process. All hollows need to be filled and built up earth removed and temporary channels provided so the flood water beneath the sub-floor drain away from the houses.

Electrical inspections after flood inundation is a must

12 January 2011

ENERGEX is urging all property owners whose premises have been inundated by floodwaters to ensure they are inspected by a licensed electrician before using or reconnecting electricity.

Buildings that have suffered floodwater inundation may have significant damage to the electrical circuitry and appliances and could present potential safety risks.

ENERGEX says it’s not worth risking a life for the sake of an electrical inspection.

Electricians can be found in the Yellow Pages, local newspaper classifieds or by contacting the Master Electricians Association.

People with solar panels on their roofs should also be aware that although mains power is cut from their home, the panels may still be generating electricity and present a electrocution danger.

ENERGEX currently has more than 100,000 homes and businesses cut from the power network due to flooding. We thank the community for their patience during this ongoing situation.

Floods and storms

Workplace health and safety laws when cleaning after floods and storms

Employers and workers involved in the flood and storm recovery efforts must still remember their obligations under Queensland's health and safety laws.
These laws are in place to protect Queenslanders. By being vigilant and maintaining safety during this difficult time, you can help reduce the risk of death, injury and illness to yourself, your workers and others involved in the clean up and repair effort.

Steps for planning to do work safely

Check that an electricity clearance has been given before attempting to use it.
Identify any likely asbestos containing materials or dangerous chemicals.
Assess what work needs to be done.
Work out the order of the work to be done so that new risks are not introduced, e.g. think about how you will get access to the areas where the work is to be done, or the possibility of creating instability from removing things in the wrong order.
Consider what could go wrong during the clean up and repair work.
Work out what tools and equipment will be needed to do the work safely.
Check the correct equipment is available and is in good working order.
Check that the people required to operate the equipment have the right skills and competencies and ensure supervision of less skilled workers is available.
Check that people allocated to perform work are not fatigued.
Make sure that workers have the correct personal protective equipment (for example rubber-soled shoes, gloves, hats, sun protective clothing and high visibility vests) and it is worn correctly.
Check that appropriate first aid, clean drinking water and hand hygiene measures are available and there is access to medical treatment in the event of an injury occurring.
Check that there is access to toilet facilities.
Highlight any counselling services available to staff and encourage their use.

Working at a height

Install handrails if necessary, such as when working on a roof or from a platform above the ground where people are carrying out work that could cause them to fall, or the fall itself could cause a serious injury.
When using a ladder:
- make sure the ladder is sufficiently sturdy
- use the ladder for the purpose it was designed for
- try to secure ladders before use
- do not use a ladder on soggy/soft ground.
Ensure surfaces are stable and access to areas with unstable floors is safe.
Be aware of anyone working below and the potential for things to fall on them.

Find more information about working at a height.

Demolition

Check that your demolition work doesn't require a licensed demolisher. Call Workplace Health and Safety on 1300 369 915 for more information. If it does require a licence, ensure a person with the right licence is engaged.
If the work doesn't require a licensed demolisher, make sure the work is undertaken by people who understand the structure, or the part of the structure, they are demolishing.
Check the location of any underground, overhead or concealed services (e.g. gas, water, electricity) prior to commencing any demolition work.

Asbestos - removal of, and work on asbestos containing materials

Buildings built before 1990 may contain asbestos materials. Removal of 10m² or more of asbestos containing material must be done by a licensed asbestos removalist. You can download a poster Where to look for asbestos which shows the potential location of asbestos materials in a house.
Avoid removing asbestos materials unless absolutely necessary, e.g. only remove asbestos sheeting that is already broken and dislodged.
Avoid breaking asbestos material.
Do not use power tools or any abrasive materials on asbestos containing surfaces.
Avoid using high pressure water to clean the surface of asbestos materials:
- care must be exercised when cleaning the surface of asbestos materials so as to avoid damage and the release of asbestos fibres
- roofs containing asbestos materials must NOT be cleaned using high pressure water cleaners or water blasters
- other surfaces containing asbestos materials such as walls should be cleaned using water hoses or by hand. Painted asbestos containing materials are less likely to release fibres and can be cleaned with slightly higher water pressure
- regularly check the surface of the material you are cleaning to ensure it is not being damaged
- more information is available on Cleaning asbestos cement roofs.
Avoid walking on corrugated asbestos roofs as they may collapse from the weight.
Avoid using power tools to drill or cut asbestos materials.
Make sure asbestos materials are wet during removal and other work; isolate electricity to wet areas.
Wear disposable coveralls with a hood as well as an approved particulate respirator (Class P2 – this will be marked on the packaging) when removing asbestos.
Thoroughly wash hands, shower and wash hair after handling or after suspecting you may have handled asbestos materials.
Double bag/wrap all asbestos materials and waste and call your local authority to find out where to properly dispose of any asbestos products.
Safe work procedures including for low speed drill/hand drilling and hand sawing asbestos containing material, and the removal of less than 10m² of asbestos containing material, including wrapping waste and clean-up after the work is completed, can be found in Asbestos: a home renovator's and tradesperson's guide for minor work in domestic premises guide (PDF, 1.6 MB).

Download the fact sheet on Asbestos - cleaning and/or removing asbestos containing materials (PDF, 157 kB)

Chemical hazards

Floods and storms may have buried, moved or damaged hazardous chemical containers including corrosives, oils, pesticides and industrial chemicals. To safely handle and dispose of hazardous chemicals, the following should be considered:

Try to identify chemicals and their hazards using labels and markings. If water has removed the label, seek expert advice and chemical identification from a waste management consultant.
If a container may cause potential risk, (e.g. bulging under pressure, leaking, or in a precarious position), isolate the immediate area and call '000'. The Queensland Fire and Rescue Service is equipped and trained to deal with these situations.
Wear personal protective equipment such as chemical resistant gloves, protective eyewear, closed footwear and long sleeved shirts and pants to minimise exposure to skin.
Isolate chemicals from general waste.
Segregate chemicals based on the condition of the container (damaged or undamaged) and based on reactions with one another, for example oils and dry pool chlorine may cause a fire.
In Brisbane, contact the city council on 3403 8888 to arrange collection of hazardous waste. For more information see Brisbane City Council's flood fact sheet. Areas outside the Brisbane region should contact their local authority for advice on disposal of the waste.
Take precautions to protect the area from further damage during the clean up, such as preventing mobile plant (e.g. earth-moving equipment) coming into contact with containers, particularly gas cylinders.
Monitor atmospheres in enclosed spaces using a suitable air monitoring device (e.g. gas detector) where plant and equipment exhaust is generated. Ensure exhaust gases are ventilated to prevent the build up of contaminant exhaust gases such as carbon monoxide. Reduce this risk by operating generators and other fuel-powered equipment outdoors wherever possible. For example, pumps used for water removal from a basement.
Chemical processing and handling equipment that has been flood or storm affected should be checked prior to operation, ensuring electrical installations are checked by a qualified electrician.
For gas supply systems e.g. town gas or fixed tank installations contact your supplier regarding the safe return to operation.
Ensure the appropriate decontamination of clothing and equipment after handling or coming in contact with chemicals. Wash down clothing with water and launder separately.

Download the fact sheet on Dangerous or hazardous goods - cleaning and/or disposing of dangerous goods and chemicals (PDF, 149 kB), the Guide for safe storage and handling of dangerous goods and view other information on dangerous goods storage and handling.

Slips, trips and falls

Keep work areas as clear and dry as possible.
Wear suitable footwear with good grip.
Try to avoid climbing on objects or surfaces; use equipment such as ladders or step stools wherever possible and safe.
Try to make sure there is adequate light in work areas.

Download the Guide for preventing slips trips and falls (PDF, 702 kB) and view other information on slips, trips and falls.

Biological hazards

Maintain good hand and personal hygiene. Wash your hands well after contact with mud, flood water and contaminated items and equipment, and before eating and drinking.
Clean and cover cuts and wounds. Talk to your doctor if you get a wound as you may need a tetanus booster.
Where contact with flood water and mud is unavoidable, wear enclosed footwear, gloves and suitable clothing.
Take precautions to avoid mosquito bites.

Environmental conditions after floods and storms increase the risk for infectious diseases. Skin infections, diarrhoeal disease, respiratory infections and mosquito-borne diseases are the most common infectious diseases after floods and storms in Queensland.
Less commonly, contact with floodwater can cause serious illness such as leptospirosis and melioidosis. See your doctor if you become sick after contact with floodwater or if you need a tetanus booster.
More information about disaster management, including how to manage mould and other sources of disease, is available from Queensland Health.

Fatigue management

Roster shifts so that workers/volunteers have the opportunity to sleep continuously for 7 to 8 hours in each 24 hour period.
Rotate shifts forward rather than back.
Limit number of consecutive night shifts to four.
Finish night shifts by eight am.
Allow a minimum of 12 hours between consecutive shifts.
Roster at least two full nights sleep after the last night shift.
Provide frequent rest breaks during shifts.
Provide transport where possible to minimise the risks associated with commuting.
Provide an area/room for workers/volunteers to sleep before commuting home.
Schedule safety critical and complex tasks during the daytime (when workers/volunteers are most alert).

Download the fact sheet on Managing fatigue (PDF, 107 kB) and view other information about fatigue.

Psychological stress

The emotional impacts of these natural disasters on workers may not come to the surface for a little while. To minimise the risk of psychological stress on workers employers should:

Highlight counselling services available to workers and encourage them to use them.
Consult with workers when setting realistic work targets and priorities for completion of clean up and repair works.
Consult with workers about any changes to their roles, work tasks and broader business changes, and where possible allow their input in decision making.
Hold regular worker/team discussions on additional pressures/challenges.
Provide 'time out' areas for workers to distance themselves and take breaks from demanding work tasks.
Recognise and reward workers for their efforts.

Manual tasks

Use mechanical aids like wheel barrows, trolleys, earth-moving equipment.
Use long handled equipment such as shovels and brooms.
Provide adequate numbers of people to do the work.
Ensure people have adequate rest breaks.
Place rubbish skips close to where the work is being done.
Where team lifting is the last resort, ensure adequate numbers of people are provided, there is good communication about what is required and a leader is appointed.
Ensure equipment is in good working order.
Consider the physical capacity of your workers and assign their work appropriately.

Displaced fauna

Check in and under objects before attempting to move an object as snakes, spiders and other undomesticated animals may be taking refuge in the dry location. Startling these animals may cause them to become aggressive and attack.
Do not attempt to kill snakes as most snake bite incidents occur when someone has attempted to strike and kill the snake.
Engage a wildlife removal specialist to remove snakes from buildings.
Rodent Control After a Flood
Safety Precautions and Elimination
Following floods, rats and other rodents may move into buildings to escape flood waters. Snakes are often forced into places where they are not usually found. Upon re-entering flooded homes or buildings, you will need to be wary of these possibilities. Rats can carry disease and parasites, while snakes may be poisonous or at least frightening. Neither pose serious problems but the chance of an incident increases after a disaster.
Where the Rats Are
Because of the danger of rat infestation, use caution when entering flooded buildings:
Carry a solid club and a flashlight.
Inspect likely hiding places for rats. Check closets, drawers, mattresses, appliances, upholstered furniture, stacks of clothes or paper, dark corners, attics and basements.
Be extremely careful when approaching rats. They may be aggressive.

Controlling Rats

If rats continue to be a problem after flood waters recede, contact your county Extension agent or professional pest control operator for advice. If you proceed on your own be extremely careful with any rodenticide or trap. To minimize rat problems:

Remove trash piles and piles of damaged furniture or equipment. Store materials on platforms or shelves 12 to 18 inches above the ground.
Remove food sources. Store food supplies in rat-proof bins or containers. Suspend garbage containers from trees or posts. Remove animal carcasses, as they may attract rats.

If you are bitten by a rat, wash the wound with soap and water and see a doctor immediately. Rats may carry diseases and at the least, rat bites can cause infection. If the rat is captured or killed, health authorities may wish to check it for rabies or other diseases. When picking up a carcass, use the inside of a plastic bag to avoid touching it. Double-seal it in plastic and freeze until further notice.

Flood Water Cleanup Procedures Indoor Environmental Quality

Introduction

Due to the numerous incidences of flooding reported throughout the country these last few years coupled with the increasing concerns about mold contamination in buildings, we thought it appropriate to have these guidelines for property managers. Note these are general guidelines that may need to be modified for specific circumstances and they may not be appropriate for all conditions.
Floodwaters do colossal damage to property. Wood swells and rots, wallboard can disintegrate and most paper items are destroyed. The mud, soil, insects, small animals and refuse carried in by the water penetrate everything. The disposal of carpets, fabrics, furnishings, wallboard and wood sections, plus the cleanup and repainting costs are usually covered by flood insurance — if the property owners are lucky enough to have such coverage.
What will not be covered by insurance are many of the long-term problems that manifest themselves weeks, months or years after the floods have receded. At the top of the list of future problems are those due to the ubiquitous molds. Molds and mildew grow on virtually anything and their multiplication and spread is prompted by dampness. Once well established in a property, they are difficult to eradicate. Spores from these fungi are minute and are light enough to be carried on air currents throughout the property. They may well settle on surfaces and remain in a dormant state for months or even years. Then, when conditions are right — perhaps simply an increase in a room’s relative humidity, new colonies germinate and re-infest the whole property again.

Classification of Flood waters

Before defining the most appropriate techniques for a cleanup it is important to first recognize the nature of the water incursion. Depending on the source of the water, different standards for proper remediation are required. Here the classification of water damage promoted by the Institute of Inspection, Cleaning and Remediation Certification (IICRC) is of help. This classification takes into account the water source, its contents and its history, thus:

Clean Water:

Used to identify water that does not pose an immediate health threat. This applies to waters that do not contain contaminants and includes broken water lines, malfunctioning appliances, toilets holding tanks, snow melt and rainwater. However, over time, say within 48 hours, and especially after contact with building surfaces, clean water can progress to category two, gray water.

Gray Water:

This may cause a health risk since the waters may contain chemical or biological contamination. These waters include discharges from dishwashers, washing machines, sinks, showers, aquariums and waterbeds. Again time is of importance, after 48 hours in contact with building surfaces, most gray water should be reclassified as category three, black water.

Black Water:

This is a positive health risk. These waters are presumed to contain multiple and potentially harmful contaminants. It includes flood waters containing soil and any sewage waters. All raw sewage is contaminated with microbes, including bacteria, protozoans, molds, fungi and viruses. Many of these are pathogenic to humans. Microbes from this source certainly cause many diseases, including Cholera, Typhoid, Hepatitis, and numerous other gastroenteritis type illnesses. Common symptoms include diarrhea, vomiting, nausea, fever and severe abdominal cramps. Contamination from fecal matter also includes the so-called “cruise-ship virus”, correctly called Norovirus, and parasitic illnesses due to infections from Giardia or Cryptosporidium. Any contact with contaminated water or surfaces can lead to contamination of the skin and subsequent transfer to the mouth. During and after the drying out process, unless proper precautions are taken, infections may occur through the inhalation of microbes
contaminating aerosols and airborne dusts. Even the dusts themselves may trigger allergies in sensitized individuals.

Priority One―Dry Out Your Property

Clean & Gray Water Floods

Time is of the essence. Provided that the property is thoroughly dried out within 48 hours and the source of the problem arrested, in the case of both clean and gray water flooding, further problems are unlikely. Remember, in the case of gray water flooding, after 48 hours you should treat the problem as a black water situation.

Black Water Floods Including Sewage Waters

In the case of river waters spilling their banks, excessive rain-waters washing soil particles into buildings or sanitary sewer back-ups or overflows in buildings there is a certain health risk. Thus, considerable care and due-diligence inspections, testing and documentation is advised. Absent obvious flooding, sewage leaks inside buildings may be caused by blocked or damaged pipes, under-sized sewer systems or simply by excessive outdoor rains penetrating into leaky sewer pipes. After every black, or sewage water, incident in a building the owner can anticipate the following questions from the occupants:
• Has the cleanup been totally successful?
• Was it safe to reoccupy the contaminated area?
• How can this be proven with confidence?

Guidelines for Handling Sewage Contaminated Articles

You should observe and ensure that professional and qualified sewage remediation contractors apply the following guidelines. It is not advisable for sewer spills to be cleaned up by in-house building management personnel unless they are equipped with the correct equipment and training.

The first priority is to ensure the use of proper Personal Protective Equipment (PPE). Rubber boots, rubber gloves, splash-proof eye goggles and a facemask rated at a minimum of 95% efficient for fine particles are essential. After removing the PPE always ensure that workers’ hands and faces are thoroughly washed with copious amounts of soapy water.
Be certain before allowing workers into any flooded area that there is no chance of a live electrical outlet in contact with the water.
Dry the area as quickly as is possible, use wet vacuums or water pumps to suck up the contaminated waters and dispose of it in sewers, not storm-water drains. It is illegal to deliberately discharge so-called “black water” which is likely to contain sewage and other contaminants, including pesticides, heavy metals, organic and inorganic chemicals into storm water drains.
Use circulating fans and area dehumidifiers to boost air circulation and remove water vapors from the air.
Expensive rugs and smaller area carpets can be wrapped in plastic and removed from the building for professional cleaning by qualified contractors. Sewage-contaminated rugs should not be sent to ordinary commercial carpet cleaning contractors. Wall-to-wall carpeting and its underlay, once contaminated by sewage waters, can rarely be cleaned properly and for health reasons it is safer to dispose of them. Furthermore, once wall-to-wall carpet has been thoroughly wetted it rarely returns to its custom size and this alone constitutes a problem.
All wallboard materials that have been contaminated by sewage waters should be cut out and removed. Extend the area for removal approximately 12 to 18” beyond the watermark or height of the floodwater. Wallboard will draw contaminated water via capillary action up the core of the board above the waterline.
Discard any ceiling tiles that have been contaminated by sewage waters.
All insulation materials, whether Styrofoam, fibrous glass, sponge rubber or cellulose wetted by black water should be discarded.
Most solid wood materials can be cleaned and allowed to dry out. However, hollow wood doors usually have cardboard spacers inside that loose their shape when wet. Doors and furniture made of wood laminates, especially plywood, tend to delaminate and peel apart. If these items buckle and delaminate after flooding they should be discarded.
Vinyl wall coverings seal the wall and keep it from drying out. The wallpaper paste bonding the wallpaper to the walls usually contains cellulose, a favorite food for molds. For these reasons, all wall coverings that are wetted should be removed and discarded.
Any upholstered furniture, fabrics or furnishings wetted by sewage-contaminated waters, and furniture made from pressed wood products, will be difficult to properly decontaminate and the safest course is to dispose of them.
Any contaminated papers, cardboard boxes or files should be disposed of.
Any foodstuffs, or opened drink containers should be disposed of. Even screw-capped containers of food or drinks submerged by sewage-contaminated waters should be discarded.
All surfaces of solid woods, concrete, vinyl tile, ceramics, metal, glass and plastic can be well cleaned with water and detergents before sanitizing them with a dilute bleach solution. The optimum mixture is one-part domestic bleach to ten-parts of water. Ensure that the bleach solution remains in contact with the surface for at least one minute. Thereafter, re-clean with a detergent solution and allow all surfaces to dry thoroughly. Note that this bleach solution may discolor some finishes.
Any air filters inside of main or supplementary air handling systems, once wetted should be immediately replaced.
Never eat, drink or smoke in any areas suspected of being contaminated with sewage.
If illness occurs within 72 hours of such a cleanup, workers should contact their doctor immediately.

Post Cleanup Certification of Due Diligence

Healthy Buildings can provide a final visual inspection and testing of the previously contaminated area. In addition to a thorough visual inspection, Healthy Buildings recommends four series of analytical tests:

a) Moisture meter readings of surfaces to confirm that all previously wetted materials have thoroughly dried out.

b) Microbial sampling of suspect surfaces predominantly focusing on coliform bacteria. These bacteria are a collection of relatively harmless microorganisms that, under normal conditions, live in a symbiotic relationship with their host, inhabiting the intestines of man and animals. They aid in the digestion of food. The most common of these is Escherichia coli, usually referred to as E.coli. Thus, it has become an industry practice to test for these types of organisms, especially total coli forms, and E. coli as an indicator of the presence of fecal material. They indicate a potential health risk when present, as there is a real likelihood that other pathogenic species are also present, possibly including those that cause typhoid fever and viral or bacterial gastroenteritis. Further cleanup work is indicated.

c) Some researchers point out that sampling for microorganisms alone, such as the coli form bacteria, may yield false negative results. Traces of disinfectants, variations in temperatures, desiccation of the samples etc. may kill the coli form bacteria but other harmful substances may still be present. There are several additional tests that may be employed to help ensure even traces of fecal contamination have been eliminated. These include fecal sterol and endotoxin testing. Contact Healthy Buildings for more details.

d) Air-O-Cell samples for airborne mold spores. Samples to be taken include at least one sample from the previously contaminated area, plus two control samples—one from an indoor space that was never exposed to the flooding and one from outdoors. These are truly “due-diligence” type samples only. Since the flooded area recently contained moisture it is logical for the occupants to fear mold, and in Healthy Buildings experience, satisfactory indoor air counts compared to control levels help alleviate occupant concerns.