Lead Inspector Assessor Flashcards
lead symbol and latin name
Pb, plumbum (liquid silver)
Why was lead used
durable, keeps colors bright, blocks radiation
Dr. Alice Hamilton
occupational health physician first wrote about hazards of lead 1913
LEAD BASED PAINT
≥ 1.0 mg/cm2 (XRF)
≥ 0.5% by weight (chip sampling)
≥ 5,000 ppm
LEAD CONTAMINATED DUST
≥ 40 ug/ft2 - interior floors
≥ 250 ug/ft2 - interior horizontal surfaces
≥ 400 ug/ft2 - exterior horizontal surfaces
Lead based paint still used today for
Industrial use, usually coatings for bridges etc.
Consumer Product Safety Commission did what in 1978?
restricted lead in coatings to < 600 ppm, it later decreased more in 2008
Lead based paint was still used through what year
- Banned in 78 but still sold for about 2 years
LEAD CONTAMINATED SOIL
≥ 400 ppm child’s play area
≥ 1,000 ppm all other areas
Tetraethyl Lead
was used in gasoline, anti knocking agent.
Clean Air Act
banned sale of leaded fuel for all uses, 1996
When was leaded gasoline phased out?
1970s in a 20 year phase out
Drinking Water Lead
15 ppb
1 exposure for occupational workers
lead fumes
1 exposure for children
lead dust, oral route
Chaca Chaca
mexican candy with lead in wrapper
where is lead found on cans
in seams, usually cans produced out of country
Kohl
middle eastern eye liner with lead
1g = ___ ug
1,000,000 ug
ug/m3 is used for what
air
ug/ft2 used for what
surfaces (dust wipe sampling)
ug/dL used for what
BLL
mg/cm2 used for what
lead based paint, chip sampling
mg/kg used for
soil
ppm used for
usually soil or lead based paint
CDC BLL level of concern for children
10 ug/dL
lead is absorbed through _____ and gradually stored in ___
lungs/stomach, bone/tissue
children/pregnant women absorb ___% lead
adults absorb __%
50
10-15
lead poisoning symptoms
headache, abdo pain, anemia, learning difficulties, kidney disease, heart disease, speech problems, high blood pressure, wrist drop
half life blood lead
half life bone lead
28-36 days
>30 years
blue black line on gums
anemia due to lead poisoning, burton’s line
how does lead affect blood
makes it difficult for blood to carry oxygen, CNS affects
chelation therapy
to remove lead poisoning. also removes electrolytes. done by physician.
Title x
1992, Residential Lead-Based Paint Hazard Reduction - required federal agencies to establish rules about working with lead.
Two step plan of Title X
evaluate hazards, reduce hazards through interim controls or abatement
Target housing
housing constructed prior to 1978
Disclosure Rule
1996, landlords must disclose lead presence
RRP
Renovation, Repair and Painting Rule, 2008 workers must be trained
HUD Guidelines
are incorporated by regulation (CDPH Title 17). They provide how to identify lead-based paint hazards and how to control them
Ambient Air Quality Lead Standard
1.5 ug/m3 based on 30-day average
Lead hazard evaluation
onsite investigation of lead based paint or lead hazards for PUBLIC and RESIDENTIAL buildings
Reporting for lead hazard evaluation
CDPH form 8552 within 30 days of completion
How long does I/A retain 8552 form
3 years
What are the reports/forms/documents for a completed lead hazard evaluation
CDPH 8552, site map, foundation diagram, summary of each test method, device and sampling procedure, description of testing and sampling locations, results of lab analysis
Define abatement
an activity designed to reduce/eliminate lead hazards or lead-based paint for PUBLIC or RESIDENTIAL buildings
permanent vs. temporary/interim abatement
permanent - >20 years
temp < 20 years
form to report abatement
CDPH 8551
who can do permanent abatement
CDPH supervisor, workers must be CDPH certified also
clearance inspection
is required for permanent abatement
who can do a clearance inspection
CDPH I/A or CDPH monitor
When is 8551 submitted
5 days prior to abatement activity
does interim abatement require 8551
yes, but not done by certified individuals
Where does an 8551 need to be posted
all work area entrances until abatement has been completed. for permanent abatement until clearance inspection completed.
senate bill 460
requires employers to have an IIPP: injury and illness prevention program
lead Action Level and what it requires
30 ug/m3 over 8-hour TWA. requires: medical surveillance, training, hand washing faiclities
PEL for 8-hr and requirements
50 ug/m3 8hr TWA. surveillance, training, hand washing, respirators, showers, change areas, eating areas, PPE clothings, warning signs, etc.
how to calculate PEL for other work hours. what is PEL for 10 hr
400/# hours, 40 ug/m3 for 10 hour
trigger tasks 1
manual demo, scraping, sanding
heat gun
power tool with dust collection
spray painting with lead paint
trigger tasks 2
using lead mortar lead burning manual demo (more serious) rivet busting power tool without dust collection cleanup using dry abrasives abrasive blasting enclosure and removal
trigger tasks 3 (4)
abrasive blasting
welding
cutting
torch burning
when is medical surveillance required
for any employee occupationally exposed on any day to lead at or above 30 ug/m3 on an 8-hour twa
initial medical surveillance
one-time BLL and ZPP
ongoing medical surveillance is required when
over 30 ug/m3 for more than 30 days in 12 months
biological monitoring frequency for <40 ug/dL
q 2 months for 6 months, then 1 q 6 mo
biological monitoring frequency for 40 to <50 ug/dL
q 2 months until 2 consecutive BLL < 40 ug/dL
medical exam
information on removal requirements
medical removal
when 2 BLL within two weeks ≥ 50 ug/dL.
BLL monitoring if medically removed
monthly until 2 consecutive BLL equal to or less than 40 ug/dL
how long are medical records maintained by employer
30 years after employee leaves
lead notification to calOSHA is required when
24 hours prior
exceptions to CalOSHA reporting
if ongoing work then once a year
not required if:
1. less than 100 ft2 or 100 LF
2. only torch cutting/welding less than 1 hr on any shifti
3. not lead based paint by definition (less than 0.5%, 5,000 ppm or 1.0 mg/cm2)
5 examples of engineering controls and safe work practices to avoid lead exposure
contain work area clean change area handwashing facilities showers break area
should you work on paint removal with it being wet or dry
always wet mist areas to prevent lead dusts
OSHA 300 log
an annual summary of on the job related employee injuries and illnesses. Can be requested by employee
when can employer rely on earlier exposure assessment?
if monitoring results are on hand from similar assessment taken within 12 months
how often does an employer need to assess exposure to lead when employee is above action level but at or below PEL
every 6 months
how often does employer need to assess exposure if employee is above PEL
once every quarter
lead exposure assessment results must be given to employee within ___ days
5 days
flow rate for lead exposure assessment
1-4 liter per minute (LPM)
What is an MCEF 0.8 micro used for
filter for lead exposure assessment.
filter loading rate for lead exposure assessments
2mg total of dust
how often to check the pump during lead exposure assesment
every 2 hours
calibration methods of sampling pumps (for lead expsure assessment)
bubbler or rotameter. bubbler is preferred and considered primary method.
when does an employee wear a respirator
above PEL, when requested by employee
respirators for trigger 1, trigger 2, trigger 3
- above PEL (50 ug/m3) but not more than 10 x PEL (500 ug/m3) HALF FACE APR
- above 10x PEL (500 ug/m3) but not more than 50x PEL (2,500 ug/m3) FULL FACE APR
- above 50x PEL (2,500 ug/m3) PAPR
half face and full face aprs are __________ pressure respirators
negative
papr and sar are _____ pressure respirators
positive
sar standards for
supplied air respirator
what air grade is used for SARs
grade D (same as SCUBA)
3 requirements of wearing respirator
medical approval
training
fit testing
how often are cartridges changes out on respirators
in accordance with your respiratory protection program (usually when breathing becomes difficult)
qualitative vs quantitative fit testing
qualitative - voluntary response to challenge agent
quantitative - measures challenge agent leakage
quantitivate fit testing is required if exposure is _____ x PEL
100
APF
assigned protection factor (minimum anticipated protection by properly functioning respirator class)
SWPF
simulated workplace protection factor - surrogate measure of workplace protection provided by a respirator
WPF
workplace protection factor - measure of protection provided by respirator of worker
MUC
maximum use concentration (max amount of lead a respirator can protect you from)
PEL X PF =
MUC
protection factor of:
- half face apr
- full face apr
- papr, sar
- 10
- 50
- 1,000
HEPA
high efficiency particulate air, filter. 0.3 micron, 99,97%
what is most universal type of HEPA
p100
combination cartridge’s which two types of contaminants
particulates AND gases/vapors
type of air required for SAR
grade D (same as scuba)
fit testing is required how often
annually
two types of user pressure checks
positive pressure check - close off exhalation and breath out. mask should remain sealed
negative pressure check - close off inhalation and breath in. mask should collapse
7 steps in cleaning respirator
- remove filter
- wash in warm water with mild detergent
- rinse in warm water
- disinfectant, 50 ppm chlorine or 50 ppm iodine or equivalent
- rinse in warm water
- hand dried with lint-free or air dry
- reassemble
When is PPE clothing required
when PEL is exceeded, or performing trigger tasks. must be supplied at no cost
how often is PPE clothing provided
weekly unless over 200 ug/m3 (then daily)
HSC Section 105280 does what
gives status authority for environmental investigation
laboratory cerification for lead analysis
NLLAP
CCR, Title 17 covers what
- accreditation/certification of lead workers
- work practices for lead (public and residential buildings)
- RRP requirements which apply to renovations, remodeling, painting
CCR, Title 8, Section 1532.1 covers what
CalOSHA construction safety orders for lead: defines PEL for lead, respiratory protection requirements, housekeeping, medical surveillance, training, communication hazards, job notification
CCR, Title 8, Section 5144
CalOSHA respiratory protection Program
CCR, Title 8, Section 1509
Construction Safety Orders, Injury and Illness Prevention Program (IIPP)
Title X outlined two types of ways to evaluate lead hazards in a residential building
- risk assessment
- paint inspection
or combination of both
lead hazard screen assessment. what is it. what requirements must be met for one to be conducted
an evaluation less detailed than a full risk assessment.
building must be:
- in good condition
- probability of finding lead based paint hazards is low
steps of lead hazard SCREEN risk assessment
- tour of dwelling to determine building condition and is eligible for screen risk assessment instead of full risk assessment
- collect paint samples of any paint that is in poor condition (or measure with XRF)
- two composite dust samples (floor and window troughs) of 4 locations: child’s play area, child’s bedroom, main entryway and one other location
no water or air sampling is done.
paint quality rating for exterior components with large surface areas: intact, fair and poor
intact: entire surface intact
fair: ≤ 10 ft2
poor: > 10 ft2
paint quality rating for interior components, large surface areas (walls/floors/doors/ceilings)
intact, fair and poor
intact: entire surface intact
fair: ≤ 2 ft2
poor: > 2 ft2
paint quality rating for interior and exterior small surface areas (window sills, baseboards)
intact, fair, poor
intact: fully intact
fair: ≤ 10%
poor > 10%
paint quality rating for exterior components with large surface areas: intact, fair and poor
intact: entire surface intact
fair: ≤ 10 ft2
poor: > 10 ft2
paint quality rating for interior components, large surface areas (walls/floors/doors/ceilings)
intact, fair and poor
intact: entire surface intact
fair: ≤ 2 ft2
poor: > 2 ft2
paint quality rating for interior and exterior small surface areas (window sills, baseboards)
intact, fair, poor
intact: fully intact
fair: ≤ 10%
poor > 10%
intact vs fair vs poor surfaces
intact - monitor to ensure they don’t become hazardous
fair - should be repaired but not yet considered a hazard
poor - considered a hazard and should be corrected
three types of paint deterioration
surface, bulk and layered
surface deterioration
chalking (find powder), worn/chipped (friction or mechanical), mildew
three steps of a risk assessment
visual inspection
testing deteriorated paint and paint on surfaces
testing dust from floors and windows
layered deterioration
blistering, peeling, sclaing
how to determine condition of friction and impact surfaces
operate three to four windows and doors
three steps of a risk assessment
visual inspection
testing deteriorated paint and paint on surfaces
testing dust from floors and windows
difference in final report for risk inspection vs paint inspection
for risk inspection the report identifies remedies, paint inspection just shows test results.
does paint inspection test for soil or dust?
no
composite sampling
can be used for dust wipe samples of common components in different rooms. You can do up to 4 dust wipes in a composite sample and there is a minimum of 4.
what is a spike sample
known positive dust wipe sample to be submitted for analysis as a control
where are dust samples collected from during risk assessment
floors, window sills, window troughs/wells
composite sampling
can be used for dust wipe samples of common components in different rooms. You can do up to 4 dust wipes in a composite sample.
dust sampling for community buildings/day cares/recreational or other child occupied spaces
for up to 2,000 sq ft
2 samples high traffic floors
1 sample window sill
1 sample window trough.
for spaces larger than 2,000 sq ft collect 1 extra sample for floors and windows for each increment of 2,000 sq feet round up
of dust wipe samples if single surface dust sampling is conducted
6-8
dust sampling in common areas of multifamily housing
take an additional two samples from entry area floor and one from first floor landing.
dust sampling for community buildings/day cares/recreational or other child occupied spaces
for up to 2,000 sq ft
2 samples high traffic floors
1 sample window sill
1 sample window trough.
for spaces larger than 2,000 sq ft collect 1 extra sample for floors and windows for each increment of 2,000 sq feet round up
in risk assessment should paint sampling or dust sampling be done first?
dust sampling
what are the two methods of deteriorated paint analysis
XRF or paint chip analysis by laboratory
can you use an XRF on peeling or chipping paint
no, only intact
how many paint chip samples are usually analyzed for risk assessment
usually 5 to represent similar components
composite paint chip sampling
cumulative sample of 1 square inch of paint samples. Result is to be divided by number of sub samples.
threshold for retesting of composite paint chip samples
if 0.2 mg/cm2 then no lead present. if more than 0.2 mg/cm2 then must collect separately and test.
how close to hold a heat gun to substrate for paint chip sampling
no closer than 6”
size of paint chip sampling
4 square inches (2 x 2 or 1 x 4)
what kind of container are dust wipes samples placed in
plastic tube (no baggies)
how close to hold a heat gun to substrate for paint chip sampling
no closer than 6”
size of paint chip sampling
no more than 2-4 square inches
what needs to be reported with sample to get paint chip analysis results in mg/cm2
the exact dimensions of the sample
can you use thick diaper wipes from dust collection
no
how are dust wipe samples reported (units)
ug/ft2
how many spike samples for dust wipe sampling
one per every 50 field samples.
can you use little ones diaper wipes for dust wipe sampling
no
soil sampling from play area
at least 5 but no more than 10 sub samples in a composite sample in x shaped grid
how many spike samples for dust wipe sampling
one per every 50 field samples.
how to collect soil samples
use a coring tool 1/2 inch deep
soil sampling from play area
at least 5 but no more than 10 sub samples in a composite sample in x shaped grid
lead levels measured on wipe samples depend on what two factors
- amount of dust on surface
2. concentration of lead in that dust
what should wipe sample results be after abatement for floors, sills, troughs/wells
less than:
40 ug/ft2
250 ug/ft2
400 ug/ft2
what range % must a spike dust wipe sample fall
80-120%
where does one get a dust spike sample wipe
laboratory
which sampling is more accurate, dust wipe or paint chip
paint chip
ALARA
as low as reasonably achieabable
three steps in limiting radiation
time, distance, shielding
What is NIST SRM
quality control forXRF
national institute of standards and technology
standard reference material
XRF reading units
mg/cm2
soil test units
ppm, g/kg or ug/g
What is NIST SRM
quality control forXRF
national institute of standards and technology
standard reference material
what are wet chemical field test kits
spot tests that show cehmical change to red/pink the paint reacts with sodium rhodizonate
lead check, hybrivet, d-lead
soil test units
ppm, g/kg or ug/g
risk assessments for fewer than 5 dwellings which are not similar
need to assess all individually
how many subsamples per composite soil sample
3-10
number of soils samples needed
minimum of two composes per dwelling or building samples. one from play area and one from bare soil areas in front or backyard
how far apart should soil subsamples be from one another
2-6 feet apart
Side A for single family and multifamily
single family - street side
multifamily - main entrance side
what are the three components of testing combinations for paint inspections
room equivalent
building component
substrate
does a paint inspection include the exterior
yes. the sides are not considered seperate rooms unless evidence of different paint history
Side A for single family and multifamily
single family - street side
multifamily - main entrance side
calibration frequency of XRF
3 before starting inspection
3 every 4 hours or when work has been completed for the day whichever is more frequent.
anytime instrument is turned off/at lunch etc.
How many XRF readings for each testing combination
one for each equivalent except walls (4 readings for walls per room equivalent)
how to classify XRF results comparing to PCS
below range = negative
within range = inconclusive
above range = positive
0.5% = ____ ppm
5,000 ppm
ppm is same as ____ and ____
mg/kg, mg/L, ug/g
ppb is same as ___ and ____
ug/kg, ug/L
0.5% = ____ ppm
5,000 ppm
when is aggregate testing used in a paint inspection
for multi family homes. use flow chart to determine results
what is AAS
atomic absorption spectroscopy is most common method of lead analysis in paint chips
two elements used for XRF’s and their half lifes
cobatls 57 - 270 days
cadmium 109 - 464 days
when is aggregate testing used in a paint inspection
for multi family homes. use flow chart to determine results
what is AAS
atomic absorption spectroscopy is most common method of lead analysis in paint chips
heat gun operating temperatures on low and high settings.
low 500-600 F
high up to 1100F (that is the max)
ladder safety factor for placement
1 foot out for every 4 feet up
three elements of confined space
large enough to enter
restricted entry/exit
not designed for continuous occupancy
three steps of confined space entry
recognition
testing,evaluation,monitoring
rescue
ladder safety factor for placement
1 foot out for every 4 feet up
cleaning steps after abatement
- hepa, remove poly from vertical surfaces and wash all veritcal surfaces with lead cleaner, remove floor poly and clean floors, hepa vacuum all surfaces again
- painting/sealing if needed
- after 24 hours hepa, clean then hepa all surfaces again
lead particles usually fall within ____ feet of its source
6 feet
what should be done with ventilation system during lead abatement
shut it off and seal it to prevent dusts
three steps of cleanup after abatement
hepa vacuum, wipe down, hepa vacuum
steps of existing lead work area
hepa vacuum your suit and remove booties
step into decon area
take off ppe clothing inside out
move to wash area of decon and wash face with resipirator on then remove and wash face
___ mil poly should be used for lead work
6 mil
how far to extend poly for outside abatement
10 feet
do not perform abatement work if average winds are more than
10-20 mph
what are types of encapsulants
coatings that can last over 20 years
4 methods of abatement
replacement - removal and replacement
enclosure - covering/sealing off lead painted surface
encapsulation - coating the lead painted surface
removal - remove but don’t replace
REERp
underlayment over floors, installing tile or brick over walls, installing wood paneling or dry wall over walls i
is a type of what abatement
enclosure
how long to wait after abatement before final cleanup
1 hour
4 soil abatement methods
removal and replacement
cultivation/rototilling (plant grass or lay bark etc.)
soil treatment and replacement
paving with concrete/asphalt
are open flame burning, uncontained hydroblasting, heat guns above 1100F, and machine blasting without HEPA allowed?
no
how long to wait after abatement before final cleanup
1 hour
what is TTLC
total threshold limit concentration ( a california test)
<50 mg/kg on TTLC
non hazardous waste, check class 2 or 3 landfill or if further testing needed
eq to or greater than 1000 mg/kg on TTLC
hazardous waste, class 1 landfill (kettleman city) TCLP required
what is STLC
soluble threshold limit concentration a california stat test. some landfills require.
less than 5 mg/L on STLC
non hazardous no treatment required before landfill
equal to or greater than 5 mg/L on STLC
hazardous
what happens if TTLC results are 50 mg/kg or more but less than 1,000 mg/kg
need to do either stlc or tclp check landfill
equal to or greater than 5 mg/L on TCLP
hazardous
what is a TCLP
a federal test
toxicity characterization leaching procedure
what happens if TTLC results are 50 mg/kg or more but less than 1,000 mg/kg
need to do either stlc or tclp check landfill
who can do a clearance inspection
i/a or project monitor
what are dust clearance levels
<40 ug/ft2 interior floor
<250 ug/ft2 interior horizontal surfaces
<400 ug/ft2 exterior floor and horizontal surfaces
soil clearance levels
<400 ppm childs play
<1000 ppm all other areas
how many dust samples for clearance inspection
use chart. depends on type of abatement and controls used
how many single family houses or similar units should get a clearance inspection of 20 or fewer
all
should XRF testing be done for clearance inspection
no it’s not recommended. dust wipe on floors, sills, troghs only
how soon after cleanup can clearance inspection occur
no sooner than 1 hour
soil sampling for clearance inspection
should be done only if tested initially. do composite sampling of play area and all other areas
should XRF testing be done for clearance inspection
no it’s not recommended. dust wipe on floors, sills, troghs only
lead in drinking water level
15 ppb
what are the three laboratory methods allowed for paint chp
AAS
ASV
PSV
large furniture that can’t be removed can be
sealed with single layer of plastic
before it rains abatement work should
be stopped and cleaned up
plastic required for interior window replacement
1 layer 5 feet out
are hazardous waste generators required to clean plastic prior to disposal
no
which characteristic would lead be hazardous waste
toxicity
concentrated lead waste includes
lead paint chips, hepa vacuum debris, other hazardous waste
are ahzardous waste generators required to clean plastic prior to disposal
no
large quantity generator can store waste up to
90 days
what is flashpoint of ignitable waste
140F
cond exemp small quant generate must produce less than
100 kg per month
large quanitity generator can store waste up to
90 days
according to title 17 lead certified workers and supervisors are required for what:
a permanent abatement
b interim control
c risk assesment
d clearance
a permanent abatement
which of the following is not required when filing form 8551:
a submit to cdph 5 days before work started
b a copy is posted…
c. must be submitted even for interim abatement
d. must be submitted by supervisor
d. must be submitted by supervisor
difference between law and regulation
law is written by legislature
regulation is promulgated by the enforcement agency
if the air exposure is between action level and PEL then continue monitoring air exposure every
6 months
a house hta tis being permanentely abated has several intact lead based paint doors above 15 mg/cm2 these doors may be managed as: a. non haz waste b haz waste c run tclp to confirm d i won't say anything
c. run tclp
asbestos vs lead which is more critical in consideration of removal and which for disposal
asbestos is more sensitive for removal
lead should be considered primary indicator for disposal
does an inspection survey need to be included in an abatement plan
no.
HUD CHAPTERS
1-15
1 INTRO 2 PLANNING 3 RISK ASSESSMENT 4 NONE 5 LEAD INSPECTION 8 RESIDENT PROTECTION 9 NONE 10 WASTE 11 INTERIM CONTROL 12 ABATEMENT 13 ENCAPSULATION 14 CLEANING 15 CLEARANCE
MINERAL COMPOSITE MINING LEAD
Galena
ZPP is what
zinc protoporphyrin
three types of liability
contractual
tort
regulatory
contractual liability
contractor can be liable if there is a breach in contract
what are liquidated damages
designated damages which can be claimed if certain aspects of contract are not met, for example delay of job
tort liability
occurs when there is no physical contract. three elements must be present
- there must be a duty or rule of conduct
- there must be a breach of the conduct/duty
- the breach must have caused injury
example hot coffee from mcD that burned customer
what is regulatory liability
noncompliance with federal, state or local regulations by error or omission
does a contractor need worker’s compensation insurance
yes
who does comprehensive insurance cover
covers injuries to another person caused by accident
what are the two types of insurance policies
occurrence based (covers claim if the occurrence occurred during the time the insurance is effective)
claims based (insurance covers any claim put in during the insurance effective period regardless of when the event actually occurred)
which type of insurance is more expensive
occurrence based
what are the three types of bonds
bid
payment
performance
what is a bid bond
a promise to pay some percentage of cost of job if a bidder gets a job after the lowest bidder backs out
what is a payment bond
accompanies a lead contractor to pay for subcontractors if they are not paid by the property owner
what is a performance bond
a promise to complete a job. protects usually a school for example if contractors are unable to complete a job
interim controls should only be used when
surfaces have intact paint and are structurally sound
what device is used for wet scraping
scraper with hepa vacuum
hepa vacuum method for wall to wall carpets
2 minutes per 10 ft2 side to side then 2 minutes per 10ft2 up and down
what is a beater bar
device to be used on hepa vacuum when cleaning area rugs
air exchanges per hour in negative pressure enclosure for abrasive blasting
10
newel is a component of what
stairs
balusters are what
stair spindle
methylene chloride
not allowed in chemical paint removers
needle gun is bested used on which substrate
metal
how often do you label a lead surface before enclosing
every two feet
what are the 5 prohibited lead paint abatement methods
open flame burning or torching mchine sanding/grinding without hepa uncontained hydroblasting abrasive blasting/sandblasting without hepa heat gun above 1100F
what is a j channel used for
to seal off edge of drywall
which type of abatement should have all seams and edges sealed
enclosures
wipe test area most likely to fail in clearance
troughs
smallest size dust particle visible to naked eye
50 um
