Mould remediation

Mould Remediation

Cedric Cheong Environmental Science

Mould remediation … it is not as simple as just "killing" the mould.

I’ll be back ! Stachybotrys colony on drywall paper surface.

Definition 1

 “Remediation means to treat,

contain, remove or dispose of mould, fungi or other microbes beyond which is required to repair or replace the covered (insurance) property physically damaged by water.”

Definition 2  “…to remove or clean contaminated

materials in a way that prevents the emission of fungi and dust contaminated with fungi, from leaving a work area and entering an occupied or non-abatement area, while protecting the health of workers performing the abatement.”

You are feeling hungry and are raiding the refrigerator.

You look behind the stove to discover a slice of bread you misplaced several weeks ago.

Mouldy Math

Needless to say, it is covered with mould. Clearwater Cave Malaysia

Since the mould started growing, the area it has covered has doubled each day. By the end of the eight day, the entire surface of the bread is covered. When was the bread half-covered with mould? Clearwater Cave Malaysia

Since the mould doubles in size every day, it covered half as much area one day before!

Wind Cave Miri Malaysia

OK, I've got some mould here. How do I clean it up?  Even before dealing with the mould,

you need to think about why it got there to begin with.  The key is always moisture – where did it come from?

 While remediation may get rid of the

current mould infestation, this will definitely return if you don't eliminate the source(s) of moisture.

The key to mould control is moisture control.

Solve moisture problems before they become mould problems

Prevention

Mould prevention tips  Fix leaky plumbing

and leaks in the building envelope as soon as possible.  Watch for condensation and wet spots. Fix the source(s) as soon as possible

Mould prevention tips  Prevent moisture due to

condensation

1. Increasing surface temperature •

Insulation, increased air circulation

2. Reducing moisture in air •

Repair leaks, increase ventilation (if outside air is cold and dry) or dehumidify (if outdoor air is warm and humid)

Mould prevention tips  Keep HVAC drip

pans clean, flowing properly & unobstructed.  Maintain low indoor humidity, below 60% where possible.  Perform regular building/HVAC inspections and maintenance.

Mould growth on painted drywall by leak from HVAC unit

Mould prevention tips  Clean and dry wet

or damp spots within 24 to 48 hours  Don’t let building materials or envelope stay wet. Provide drainage and slope the ground away from the foundation.

So I have some mould growing, is it really a BIG problem?  YES – if contamination left to

proliferate – high and persistent airborne spore exposures  Occupants can get sensitised develop allergies further health problems  Serious damage to structural elements in home/building – Natural decomposers

How bad can it get?

… it is just a little mould growth, SURELY it won’t spread…

Jeffrey C. May 2001

Living room sofa in a home that was flooded. Uninhabited home remained damp after it was flooded by a broken pipe on the second floor and mould proliferated on the first floor.

Jim Bagley PHH Environmental

Terry Brennan

Okay, so I have a problem. Should I just get straight into it?  Think before you act!! – Health first! • Yours, building occupants, workers

– Prepare a remediation plan & schedule of how you are going to tackle the problem. – A plan to prevent future leaks or dampness that caused colonisation is essential for effective remediation

Questions to consider before tackling remediation Are there existing moisture problems

in the building?

– Fix source of moisture first

Have building materials been wet for

more than 48 hours

– Mould growth might already have begun

Are there any hidden sources of water

or is there high humidity?

Questions to consider before tackling remediation Are building occupants reporting

musty or mouldy odours? – Mould releasing MVOCs

Are building occupants reporting

health problems?

– Are medical & health professionals involved? – Temporary relocation of some or all occupants

Questions to consider before tackling remediation Are building materials or

furnishings visibly damaged? – What to throw / save?

Has maintenance been delayed or

the maintenance plan been altered? Has the building been recently remodelled or has building use changed?

Other issues to consider before remediation  Hidden Mould  Visible growth

might not be apparent

Hidden mould behind wallpaper

Chin Yang

Other issues to consider before remediation  Suspected

Contamination of HVAC system – Do not run system as mould spores could be transported to non-contaminated areas

Other issues to consider before remediation Hazard communication – The building owner, management and or employer should notify occupants in affected areas of any mould contamination or remediation – Notification includes • Description of remedial measures taken • Timetable for completion

Hazard communication  Group meetings held before and after

remediation with full disclosure of plans and results can be an effective communication mechanism  Individuals with persistent health problems related to mould exposure should refer to to doctors knowledgeable about mould symptoms  Individuals seeking medical attention should be provide with a copy of all inspection results & interpretation

Basic principles for fungal remediation 1. Physical removal of mycelium from

interior surfaces 2. Removal of spores in settled dusts that may have previously been dispersed from mouldy surfaces 3. Prevention of dusts associated with clean-up from entering occupied or clean areas 4. Use of personal protective equipment by remediators

IMPORTANT!

The objective of remediation is

to remove colonisation and associated mould laden dusts. It is NOT to sterilise or disinfect interior surfaces.

IMPORTANT!  The use of biocides & disinfectants is often

unnecessary.  The physical removal of mouldy materials plus the removal of associated dusts by vacuum cleaning and damp wiping should be adequate for cleaning.  Gaseous, vapour-phase or aerosolised biocides could pose health concerns.

IMPORTANT!  Disinfectants are intended to be applied to

thoroughly cleaned materials are are used to ensure that most microorganisms have been killed.  Therefore DO NOT USE disinfectants / biocides, instead of, or before, cleaning materials with soap or mild detergent.  Remember - The key to mould control is moisture control

Health & Safety  Remediation will disturb mould & mould

spores resulting in release/resuspension of airborne spores – Airborne spore concentration can exceed 106 m-3 air when mouldy materials are disturbed

 Protection of building occupants,

investigators, remediators, wider public

Worker Protection No worker, homeowner, tenant or

building occupant, who has any sort of immune suppression, asthma or mould allergy or who has recently had a severe cold or flu should undertake remediation work whatever the size.

What Personal Protective Equipment do you use?

Personal protective equipment (PPE)  Persons involved in

clean-up activities must use PPE

– Must be trained, have medical clearance, fit tested by trained professional • Skin and eye protection • Respiratory protection • Disposable clothing

Skin & eye protection Gloves extend to middle of

forearm

– Glove material type dependant on type of materials being handled • If using biocides eg chlorine bleach or strong cleaning solution, use natural rubber, neoprene, nitrile, polyurethane or PVC

Skin & eye protection Properly fitted goggles or full

face respirator with HEPA filter

– Safety glasses or goggles with open vent holes are NOT acceptable

Respiratory protection  N-95 or TC-21C respirators (small area) – Covers nose & mouth – Filters 95% of particulates in air  Half face or full face air purifying

respirators (APR)

– HEPA filter cartridge – Filters 99% of particulates

 Full face, powered air purifying respirator

(PAPR)

– Blower to force air thru HEPA filter – Must be trained

Disposable clothing  Recommended for medium to large

remediation jobs to prevent transfer & spread of mould to clothing & to eliminate skin contact with mould  Limited – Disposable paper overalls

 Full scale – Mould impervious disposable head and foot coverings and body suit made of breathable material eg TYVEK® • Gaps around ankles and wrists sealed with duct tape

Containment barriers and dust suppression Purpose of containment is to – Limit the exposure / release of mould into areas beyond the contaminated site – Prevent mould exposure to occupants & remediators

Containment barriers and dust suppression  Extent of surface colonised (minimal,

moderate, excessive) in a room or area of a building is the most important factor to be considered in relation to use of containment barriers or dust suppression methods – Size Does Matters!

 Surfaces of all objects removed from

containment should be remediated / cleaned prior to removal – HEPA vac, damp wiping

Limited Containment  Between 1 to 10 m2

 Enclosed area should consist of single

layer 6 mil fire retardant polyethylene sheeting  Have a slit entry and covering flap on the outside of the containment area.  For small areas, sheeting can be affixed to floors and ceilings with duct tape.

Limited Containment  For larger areas, a steel or wooden

stud frame can be erected and polyethylene sheeting attached to it  All supply, air vents, doors, chases, risers within containment must be sealed with polyethylene sheeting to minimise migration or leakage of contaminants to other parts of the building.

Limited Containment  Containment area must be maintained

under negative pressure – Contaminated air does not flow into adjacent areas  Utilise HEPA-filtered fan unit exhausted outside of building.  For small, easily contained areas, an exhaust fan ducted to the outdoors will suffice.

Simple containment

1-2m2 visible fungal colonisation removed in mini enclosure. Area isolated from room by plastic sheeting and negatively pressurised by insertion of nozzle of HEPA vacuum in enclosure

Extensive fungal growth  Colonised

area isolated from rest of building and HVAC system using plastic sheeting.

Extensive fungal growth  Rooms are

depressurised thru use of one or more negative-airmachines, & discharged outdoors thru HEPA filters.  Air flow from clean areas to remediated rooms

Full containment  Contaminated surface area

greater than 10 m2  Double layer polyethylene  Decontamination chamber or airlock for entry into & exit from remediation area  Entryways to airlock from outside & from airlock to main containment areas should consist of a slit entry with covering flaps on the outside surface of each slit entry Terry Brennan

Mental Refreshment

Zaanse Schans Holland

Cleanup methods 1. Wet vacuum  Designed to collect water  Should not be used to vacuum porous materials  Used only when non-porous materials are still wet  Tanks, hoses and attachments of these vacuum should be thoroughly cleaned and dried after use

Cleanup methods

2. Damp wiping / moping  Mould can generally be removed from nonporous surfaces by wiping or scrubbing with water or water & detergent.  Important to dry surfaces quickly and thoroughly

Cleanup methods 3. HEPA vacuum  Recommended for final cleanup of remediation areas after materials have been thoroughly dried and contaminated materials removed.  Recommended for cleanup of dust that may have settled  Ensure filter properly installed and regularly replaced.  Care must be taken when changing vacuum filter – PPE  Contents disposed in well-sealed plastic bags

What advantages do HEPA vacuums provide?  Ordinary vacuums capture large particles only – small mould spores pass through the vacuum into the air.

 HEPA vacuums have special filters that capture

small particles.  A central vacuum cleaner which is exhausted to the outside also removes mould spores.  A regular portable vacuum is useful only if its exhaust goes outside the home.

What advantages do HEPA vacuums provide?

 Vacuuming removes settled dust that contains an

accumulation of mould spores over time.  Reducing the settled dust reduces mould exposure  Vacuuming with any vacuum cleaner (ordinary, central or HEPA) stirs dust and mould during the mould remediation process. – Wear a dust mask so you will not be exposed to more mould.

Is vacuuming with a HEPA or externally exhausted vacuum cleaner recommended for serious mold problems only?

 Vacuum regularly with a HEPA or externally

exhausted vacuum cleaner to prevent the ongoing accumulation of dust & moulds  The need for HEPA or external exhaust vacuuming increases with the severity of the mould problem. – If a furnishing has been wet at some time in the past or has been exposed to dampness over a prolonged period of time, vacuuming with HEPA or externally exhausted vacuum is unlikely to remove the mould growing beneath the surface. – It is better to discard the item.

Cleanup methods

4. Discard  Removal of damaged materials and sealed in plastic bags  Double bagged using 6 mil polyethylene sheeting.

Does painting over a moldy surface take care of the mold?

 Painting over mold only masks the

problem. Paint does not kill the mould nor stop it from growing.  Surfaces that are washable should be cleaned with a detergent solution, then allowed to dry.  If you are going to paint, remove any mould first.

Does cleaning stop the mould growth?  Mould will reappear until its source of

moisture is removed. High moisture levels that are not corrected can make the moulds grow back quickly.  Cleaning is only a temporary but essential measure.  For obvious reasons water must be prevented from entering the building. But you can help by controlling moisture that is produced inside the building.

If using biocides / disinfectants / bleach  Always use PPE (gloves, mask, eye

protection)  Only AFTER thoroughly cleaning & rinsing contaminated materials, a solution of 10% household bleach can be used as a disinfectant.  Using bleach straight from the bottle is actually LESS effective than diluted bleach.

If using biocides / disinfectants / bleach  Keep disinfectant on treated

material for the prescribed time before rinsing or drying – typically 10 minutes  Make sure working areas are well ventilated – Fumes can irritate eyes, nose, throat and damage clothing and shoes

If using biocides / disinfectants / bleach  When working on large structure or

area, make sure entire surface is wetted  Properly collect & dispose of extra disinfectant and runoff in environmentally friendly manner.  Never mix bleach with ammonia – toxic fumes may be produced

To throw or not to throw! That is the question!

To throw or not to throw!  Non porous and semi porous

materials that are structurally sound and are visibly mouldy can be cleaned and reused.  Cleaning should be done using a mild detergent solution  Includes – Metals, glass, hard plastics, wood and concrete

To throw or not to throw!  Porous materials such as gypsum board,

ceiling tiles, insulation & wallpaper with more than a small area of contamination should be removed and discarded.  Other porous materials such as carpet, fabrics & wallboard that can be cleaned (HEPA vacuum)can be reused but should be discarded if possible.  Visible fungal colonies may not be apparent • Prudent to also remove some of the sound material adjacent to visibly colonised surface

Carpets specifically  Contaminated carpet is often difficult to

thoroughly clean especially if backing and or padding has become wet. Consider discarding.  Flooded carpet can store mould spores for years unless it is removed from the room to dry and professionally cleaned.  Simply running fans & opening windows will not dry it out enough.

Carpets specifically  The mould will dry and every time you

vacuum, the spores will be resuspended and go into the air.  Carpets contaminated with mould cannot be effectively cleaned unless they are removed and commercially processed. It may be cheaper to discard & reinstall new carpets.

Carpet wet LESS THAN 48 HOURS 1. Remove all furniture, file cabinets etc. from

2. 3. 4.

5.

carpets Extract as much water as possible using wet vacuums Shampoo the carpet with dilute surfactant Soak with ¼ to ½ cup bleach / water solution. Maximum concentration – 1 part bleach to 10 parts water Preferable not to use a biocide, else quaternary amine compounds as biocide/cleaning compound.

Carpet wet LESS THAN 48 HOURS 6. Rinse & extract the carpet with clean water to

remove detergent/bleach residues. 7. Commercial steam cleaning of carpeting can be used in place of bleach. Vacuum system house in truck. Water heated above boiling point & used to clean the carpeting 8. Dry the carpet within 12-24 hours of treatment. After work is completed, increase room temperature and use commercial dehumidifiers, floor fans or exhaust fans to aid in the drying of the carpet.

Carpet wet MORE THAN 48 HOURS  Dependent on state of carpet &

extent of mould growth.  If carpeting becomes wet during winter with relatively clean water, the previous protocol can be used to manage the carpet and maybe salvage it.  More difficult in summertime if carpeting is not in an air-conditioned space or dehumidifiers not available.

Carpet wet MORE THAN 48 HOURS  Water damaged carpets in humid

environments often do not dry adequately.  Disposal of water damaged carpets in humid environments is often the best option.  If visible mould appears or area smells of mould – Repeat treatment process (cleaning & bleaching) – Consider replacement

Books, paper & archives

 Involves discarding mouldy items, drying

out wet materials & removing settled dusts containing spores.  Drying of water damaged or damp materials is of critical importance in restoration.  For non valuable items – discard  For important papers or books – photocopy items & then discard originals

Books, paper & archives  Freeze drying of water soaked materials reduces

fungal colonisation & evaporation of water molecules (subliming) lowers available moisture for mould growth  Goal of restoration is to lower moisture content of paper to normal range of 5-7%  For valuables – miniature aspirators to provide gentle suction thru pipette nozzle to carefully remove spores from surface of paper – Large vacuum device to remove spores if a fine screen is placed firmly over the paper to provide protection to the fragile material being cleaned.

Eeek! It's in my laundry! What do I do with mouldy clothes?  Non-washable clothing can be dry

cleaned.  Wash clothes with a detergent solution to which a cup of bleach is added.  Make sure the detergent you use does not contain ammonia.  Repeat as necessary until the mouldy odours are gone.

Eeek! It's in my laundry! What do I do with mouldy clothes?  Clothes and other items that have

been cleaned should be stored in sealed plastic bags to prevent recontamination.  If this produces clean clothes, then you're all set.  The second choice is obvious--throw it out and buy some new clothes!

Remediation procedure 

Wearing appropriate PPE the remediators 1. 2. 3.

Enters the enclosure Removes and bags mouldy materials Prior to leaving the enclosure, uses the nozzle of a second HEPA vacuum cleaner to remove settled dust from the a. b. c.

outer surface of the bagged trash surfaces of inner surface of plastic sheeting Surfaces of protective clothing and equipment

Small area clean up (Level I) < 1 m2  1 or 2 ceiling tiles, small areas on walls  Can still cause health risk & contaminate other

areas  Regular staff with suitable training on proper cleanup methods & PPE  Work area unoccupied - adjacent areas OK (exceptions)  Dust suppression & sealed bags for removal  Containment not necessary  Clean-up with damp cloth/mop & detergent  All areas post remediation left dry & visibly free from contamination and debris

Mid size isolated area clean-up (Level II)

1 – 3 m2

 Individual wallboard panels  Regular staff with suitable training on proper

cleanup methods & PPE  Work area unoccupied - adjacent areas OK (exceptions)  Work area covered with plastic sheet & tape sealed to contain dust/debris  Dust suppression, Sealed bags for removal  HEPA vacuum, Clean-up with damp cloth and detergent  All areas post remediation left dry & visibly free from contamination and debris

Large isolated areas (Level III) 3 – 10 m2  Several wallboard panels  Health & Safety professional consultation  Trained workers, with personal protection  Work area & adjacent areas covered with

plastic sheet & tape sealed  Seal ventilation ducts & grills  Work area and directly adjacent areas unoccupied - high risk individuals moved  Dust suppression prior to remediation (misting)

Large isolated areas (Level III) 3 – 10 m2  Contaminated materials thoroughly cleaned

prior to removal in sealed plastic bags  Work area & surrounding areas HEPA vacuumed & cleaned with damp cloth / mop and detergent  All areas post remediation left dry & visibly free from contamination and debris  If abatement expected to generate a lot of dust or visible concentration of fungi is heavy then use Level IV procedures

Level IV Extensive Contamination > 10 m2 contiguous  Health & Safety professional consultation  Trained workers, with full PPE (full face with HEPA,

disposable clothing gloves, face mask)  Work area fully contained, HEPA exhaust, Airlocks and decontamination room  Adjacent areas can be occupied - high risk individuals moved  Contaminated materials thoroughly cleaned prior to removal in sealed plastic bags  HEPA vacuum and clean up before barriers dismantled  Air monitoring prior to reoccupancy

Level V - Remediation of HVAC  Small areas < 1 m2 in HVAC system  Regular staff with suitable training on proper

cleanup methods & PPE  System shut down prior to remediation  Work area & adjacent areas covered with plastic sheet & tape sealed  Dust suppression prior to remediation (misting)  Contaminated materials such as paper on insulation of interior lined ducts and filters removed. – Other contaminated materials that cannot be cleaned removed in sealed bags.

Level V - Remediation of HVAC  Work area & surrounding areas HEPA

vacuumed & cleaned with damp cloth / mop and detergent  All areas post remediation left dry & visibly free from contamination and debris  Consider biocide use for HVAC components like cooling coils & condensation pans (though ACGIH disagree)

Level V - Remediation of HVAC  > 1 m2 contamination in HVAC system  Health & Safety professional consultation

 Trained workers, with full PPE (full face with

HEPA, disposable clothing gloves, face mask)  System shut down prior to remediation  Work area fully contained, HEPA exhaust, Airlocks and decontamination room  Contaminated materials thoroughly cleaned prior to removal in sealed plastic bags

Level V - Remediation of HVAC

 HEPA vacuum and clean up before

barriers dismantled  All areas post remediation left dry & visibly free from contamination & debris  Air monitoring prior to reoccupancy  Consultant supervision and air sampling prior to preoccupancy if large scale contamination

HVAC cleaning  Dirt and fungal growth on non-porous

surfaces such as sheet metal can be removed by cleaning.  However, fungal growth on porous substrate such as insulation cannot be removed by cleaning. – Physical removal of entire ducting may be required if hyphae penetrated into substrate.

Mould in Crawlspaces  Perform drainage and foundation

improvements first, if necessary. Then consider several options, perhaps in combination, to reduce moisture load in the crawlspace. – Cover soil with thick air barrier or cement over open soil – Provide powered ventilation, perhaps push/pull, perhaps on humidistat control – Remove batt insulation in joists, replace with closed cell foam

Is the job done?

 

Water or moisture problem completely fixed Mould removal completed.  No visible mould, mould damaged materials & mouldy odours present



Sampling / testing reveals similar concentrations and types of mould inside building as that of outside.

Is the job done?  No signs of water damage or mould

growth during revisit shortly after remediation  People should be able to occupy or reoccupy the space without health complaints or physical symptoms  Ultimately a judgement call – no easy answer.

Guidelines & Publications  Guidelines on Assessment and Remediation

of Fungi in Indoor Environments

– New York City Department of Health 2002

 Mould in my Home: What do I do? – California Department of Health Services Indoor Air Quality Info Sheet 2001  Mould Remediation in Schools and

Commercial Buildings – US EPA 2001

Guidelines & Publications  Bioaerosols: Assessment and Control – ACGIH 1999  Fungal contamination in Buildings: A guide

to recognition and management

– Health Canada, Environmental Health Directorate 1995

 Standard and Reference guide for

Professional Water Damage Restoration – IICRC S500 1999

Internet sources Websites – http://www.caliaq.org//iaqsheet.htm#Mold – http://www.doctorfungus.org/ – http://www.moldupdate.com/ – http://www.mold-help.org/

To come: - Case studies

Mental Refreshment

Sunset Golden Gate Bridge San Francisco