Page 16 - MGPI_Case_Study

receives four chemicals via CTMV about 200 feet from the
54
Mod B transfer area, uses a different padlock and key for each fill
line. Using different padlocks and keys for each valve prevents
55
operators from unlocking the incorrect valve with another key.

5.1.2 PIPE MARKING
Pipe markings, labels, and tags are extremely important in
process plants and all facilities that handle hazardous chemicals

to ensure that workers can identify equipment that requires
manipulation and to
Pipe markings on communicate hazards

transfer equipment that cannot be controlled
and piping should be by other means. Proper

accurate and legible. equipment identification
reduces errors of
Pipe markers should commission with
56
be placed as close to using the wrong piece of
the fill line as possible equipment or performing

Sodium Hypochlorite
Sulfuric Acid
Fill Line
Fill Line

Figure 10. Combination of fill line shapes and sizes to avoid incorrect
connections during deliveries (Source: CSB).

Color coding can also assist in ensuring proper connections.
Colors associated with each class of chemicals can be used for
53
pipe markers, couplings, fill lines and transfer piping. For
example, the facility and chemical distributor could select
orange hexagon shaped couplings and fill line receivers for
acids and square purple couplings and receivers for bases.

The CSB also evaluated whether MGPI’s practice of placing Figure 11. Neither sodium hypochlorite nor sulfuric acid fill lines had
pipe markers or identification tags affixed at connection points. MGPI
identical padlocks on the sodium hypochlorite and sulfuric acid
did have a pipe marker on the propylene oxide (PO) fill line near the
dust caps increased the likelihood of an incorrect connection.
connection point (circled) (Source: CSB).
Though not causal, the CSB found that this method could
result in an incorrect connection because the same key could 54 The MGPI onsite WWTP receives phosphoric acid, sodium hydroxide (caustic), urea,
unlock both chemicals and, as a result, could unlock the wrong and ferric chloride.
55 MGPI had locks on the transfer valves for three of the four fill lines at the WWTP. The
dust cap in error. Contrary to Mod B, the onsite WWTP, which caustic line contained a cap, intended to be secured and locked on the end of the
fill line through the cam levers, similar to the Mod B fill lines. The CSB observed that
though the cap was on the end of the caustic fill line, it was not locked at the time of
53 The American Society of Mechanical Engineers (ASME) Standard A13.1, Scheme for the incident, as one lever also appeared to be missing a split ring.
the Identification of Pipes, includes a color chart that defines color schemes for six 56 An error of commission is typically associated with performing a task out of sequence
categories of chemicals and four user-defined color options for other chemicals. by using the wrong control or entering the wrong value.
16 CSB MGPI Processing Case Study