what we learned from christchurch taking the risk out ... - PlaceMakers

FEATURESBRANZRemoving mould-contaminated materialsRecommended steps to reduce biocontaminant exposure when fixing leaky buildingsRecent BRANZ research hasshown that, where leaky buildingsare being repaired, workersare exposed to a cloud of allergenic(causing an allergic reaction),carcinogenic (cancer-causing) andtoxic biocontaminants as they strip thecladding and remove mouldy materials.Especially concerning is the dangerouslyhigh concentrations of the very toxicmould Stachybotrys in the cloudgenerated during deconstruction ordemolition. The most dangerous periodof contamination is during removal ofmouldy materials, but workers must bealert throughout the whole process.To reduce exposure to thesebiocontaminants, contractors must befamiliar and vigilant with health and safetyprocedures. After consultation with leakybuilding remediation specialists Prendos andAlexander and Co, BRANZ recommends thefollowing steps where mould contaminationhas been identified or is expected:• Contamination, decontamination andsafe zones should be established.• Where possible, internal linings andexternal joinery should remain inplace until mould decontaminationis completed, by working from theoutside, removing cladding and thencontaminated material.• If this is not possible, internal airbarriers with depressurisation of internalcontaminated zones is required tomaintain other internal safe zones.• Personal protective equipment (PPE),including overalls, safety boots,gloves, helmets, eye protection andWHAT’S THAT ALL ABOUT THEN?respirators, must be worn by all thosein contaminated zones during claddingand mould removal.• Mould should be removed before it isable to dry.• Spores and mycotoxins are likelyto stick to workers’ hair and theunprotected areas of their faces. Aclean decontamination area is requiredfor removal of PPE and washing. Onsitebasins are a minimum requirementto provide for washing before leavingthis zone and entering safe zones orleaving the site.To reduce exposureto biocontaminants,contractors must be familiarand vigilant with healthand safety procedures• On highly contaminated sites, specialistadvice must be sought, and on-siteshowers may have to be provided.• Good practices of overall removal,glove removal and hand washingmust be in place during breaks andafter work. Hands and faces mustbe washed before eating.• Disposable overalls should bedisposed of on site after use or atthe end of each day.• Disposable gloves are to be usedand disposed of after each use.• Safety boots are to remain on siteat the end of the day to minimiseTEST YOUR KNOWLEDGE!spore and mycotoxin transfer tovehicles and homes. Alternatively,boots should be thoroughly cleanedbefore removing them from the site.• Helmets, respirators and eye protectionmust be cleaned after each use withparticular care to wipe the inside ofrespirators and eye protection withdisposable wet wipes.• Breaks, especially meal breaks, mustbe taken within safe zones and mustnot be taken within the building wherecladding is being removed or adjacentto stored or transported contaminatedmaterials (such as the skip).• Clean site sheds or separate approvedareas such as a garage must be provided.• Material contaminated with mouldmust be bagged before being placedin skips. Do not break these bags ordisturb contaminated waste by dumpingheavy waste on top!• Truck drivers and others tasked withremoving skip bins full of contaminatedmaterials should also wear protectiveclothing or respirators when loadingand unloading.Indoor concentrations of biocontaminantsmay remain high once the repair iscomplete, so before handing the buildingback to its occupants, it should bethoroughly cleaned to eliminate dustand debris. It should then be tested fornon-viable spore counts and be recleanedif necessary before reoccupation.These recommendations reflect currentindustry best practice and may bemodified once wider research andconsultation has been carried out.13) a b c14) a b c15) a b cWhat is Stachybotrys?a) A non-toxic mould found in leakybuildings.b) A very toxic mould found in leakybuildings.c) It’s hard to say.16www.branz.co.nzWhat is cited as the most hazardousperiod when repairing leaky buildings?a) When removing mould-contaminatedmaterials.b) When telling the homeowner that morework is required than was first thought.c) When working at height.What should you do before handingthe building back to its occupants?a) Give them the number of a localcleaning service.b) Thoroughly clean it to eliminatedust and debris.c) Throw a party.NB: The questions and answers in this section have been produced by the publisher and do not necessarily reflect views oropinions of the contributing organisation.