The
Dangers of Spraying Ignitable Liquids at Construction Sites
Warning! Construction sites
can suddenly turn dangerous, and possibly deadly, when ignitable liquids are
sprayed. Ongoing identification and elimination of ignition sources is expected
but difficult to achieve because multiple contractors’ activities, equipment,
and materials can quickly change, especially as deadlines approach. Taking action
to prevent on-site spraying of ignitable liquids is often the safer option.
The Hazards of
Spraying Ignitable Liquid
When spray equipment is used to apply an ignitable
(flammable or combustible) liquid finish, a substantial amount of overspray is
released and can drift into surrounding areas. When this overspray mixes with
air and accumulates inside enclosed or unventilated areas, it can ignite and
cause an explosion if an ignition source is present.
Ignition sources at construction sites can include
fuel-burning heaters and vehicles, table saws and other electric equipment or tools,
welding sparks and arcs, portable and permanent lighting, temporary and
permanent electrical system components (e.g., outlets, switches), cigarettes and
static electricity.
In addition, some liquid finishes contain hazardous
ingredients that can harm eyes and skin or cause risk for health problems when
mist or vapor is inhaled.
Attention: Painters and Other Contractors, General Contractors
(GCs), and Site Superintendents
Workers Injured and Property Damaged
In 2012, a residential construction project in Seattle exploded
and burned, injuring four workers and destroying the work site.
The initial flash fire melted one painter’s gloves to the backs of
his hands causing second- and third-degree burns. Another painter working outside
on a ladder suffered impact injuries when thrown by the explosion. Two workers
of the general contractor (GC) were also injured by the blast’s impact.
The explosion happened shortly after a painter finished spraying a
flammable primer (flashpoint 21° F) onto several uninstalled doors set inside
an unventilated basement room serving as a temporary spray area. The doorway to the room had been covered with
plastic sheeting to keep overspray (paint vapor and mist) away from others
working in surrounding areas. The room and adjacent areas contained a working gas-fired
HVAC furnace, electrical outlets, switches, lighting, and other ignition
sources.
With spraying finished, the painter removed the plastic sheeting
and opened the home’s exterior doors to ventilate the area. Overspray drifted
from the basement room into adjacent areas, contacted an ignition source and
caused an explosion.
What can GCs and site superintendents do?
·
ƒPrevent risk for explosion, fire, and inhalation hazards through your required
Accident Prevention Program (or site-specific safety program). For example,
restrict spraying of ignitable liquids to off-site locations equipped with the
safety features of an NFPA 33-compliant spray booth.
·
ƒCheck with the local fire jurisdiction for fire codes that cover
spraying of ignitable liquids.
·
ƒMake contractual agreements with painting and other contractors to ensure
spraying of ignitable liquids is done off site before installation.
·
ƒThoroughly review change orders to help you spot material, equipment, and other work
modifications that could possibly add or increase risk for an explosion hazard
onsite. Follow up with contractors to help ensure risks are evaluated and
safely addressed.
·
ƒUpdate your Accident Prevention Program, as required, to reflect
current safety measures to prevent fires and explosions.
·
ƒLook for clues of onsite spraying of ignitable liquids
during required weekly safety walk-throughs. Signs include temporary
enclosures, spray equipment and containers of flammable or combustible liquids.
·
ƒInform all contractors about the dangers of spraying ignitable liquids. Discuss
this alert during required crew safety meetings held at the beginning of each
job and weekly after that to ensure prevention measures are working.
What can contractors, crew leaders and workers do?
·
ƒRead each product’s required safety data sheet (SDS). Look for a flashpoint
(f.p.) temperature in Section 9 - Physical and Chemical Properties.
·
Liquids with a f.p. up to 199.4° F are now regulated as flammable per WAC 296-901-14024
B.6.1. If this information isn’t listed, follow up with the product supplier,
manufacturer or other qualified source to get an answer before you allow use.
·
ƒDon’t assume spraying a liquid with a higher f.p. (up to and even above
200° F) is safe. These liquids can quickly create an ignitable atmosphere even when
the temperature in the work area is below (cooler than) the product’s f.p.
temperature. Ignition sources as common as a light bulb may be enough to start
a fire.
·
ƒFollow NFPA 33 standards and applicable local fire codes when ignitable liquids
are sprayed in an enclosed area.
·
ƒPay attention to other contractors’ activities, equipment and
materials that may indicate spraying of ignitable liquids.
·
ƒImmediately alert jobsite safety personnel about unsafe spraying of
ignitable liquids.
·
ƒVerify fire and explosion hazards have been eliminated
before working around spraying operations. Dispersing accumulated ignitable overspray
can be dangerous around uncontrolled ignition sources.
·
ƒShare this alert and discuss it at required weekly crew meetings.
For rules and safety resources that address ventilation, isolation
of ignition sources, safe work practices, training, PPE, respirators and other
topics, please see the Painting Hazards topic page at: www.Lni.wa.gov/Safety/Topics/AtoZ
.