Marine Fire Safety Regulations Quiz

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Questions and Answers

What is the maximum temperature increase allowed at any single point, including joints, on the unexposed side of a Class 'A-30' division during a fire test?

225 degrees Celsius above the original temperature

140 degrees Celsius above the original temperature

180 degrees Celsius above the original temperature (correct)

60 degrees Celsius above the original temperature

For a Class 'B-15' division, what is the maximum average temperature rise allowed on the unexposed side during the standard fire test?

225 degrees Celsius above the original temperature

140 degrees Celsius above the original temperature (correct)

180 degrees Celsius above the original temperature

15 degrees Celsius above the original temperature

What is a key characteristic of a 'C' class division regarding temperature limits?

It does not have specific temperature rise requirements. (correct)

It has a temperature limit of 140 degrees Celsius.

It must limit temperature rise to 225 degrees Celsius.

It must prevent temperature rise on the unexposed side.

What is the primary characteristic of a 'B' class division's ability to handle fire during a standard fire test?

To prevent passage of flame for the first half hour of the fire test. Signup and view all the answers

What is the minimum number of transverse watertight bulkheads required in a dry cargo ship with machinery amidships?

Four Signup and view all the answers

Which of the following is a mandatory watertight bulkhead in all dry cargo ships?

The collision bulkhead forward Signup and view all the answers

In a dry cargo ship with the machinery located aft, what is the minimum number of transverse watertight bulkheads required?

Three Signup and view all the answers

What is the primary purpose of the collision bulkhead?

To prevent spread of flooding in the case of a bow collision Signup and view all the answers

What is the primary function of transverse watertight bulkheads in a ship?

To contain flooding and provide structural support Signup and view all the answers

Which type of bulkhead is considered to be of little structural importance?

Minor bulkheads Signup and view all the answers

What is the main purpose of 'H' class fire divisions?

To prevent the passage of smoke and flame for 120 minutes during a hydrocarbon fire test Signup and view all the answers

Which of these fire divisions is designed to prevent the passage of flame for the shortest time during a standard fire test?

'B' class divisions Signup and view all the answers

What is the key characteristic of 'A' class fire divisions?

They are designed to prevent the passage of smoke and flame for one hour in a standard fire test Signup and view all the answers

What is a key characteristic of ‘C’ class fire divisions?

They are constructed of approved non-combustible materials only Signup and view all the answers

What is a main factor, other than preventing the spread of fire, in considering the type of bulkheads needed?

The structural strength of the bulkheads Signup and view all the answers

To what height are the strengths of the transverse bulkheads maintained?

To the strength deck, which may be above the freeboard deck Signup and view all the answers

What is the primary motivation for a shipowner to optimize watertight bulkhead spacing in bulk carriers?

To achieve a reduced freeboard and maximize permissible draft. Signup and view all the answers

According to the International Load Line Convention 1966, what condition is required for a bulk carrier to obtain a reduced freeboard?

The vessel must be able to flood one or more compartments without loss of the vessel. Signup and view all the answers

What is a key characteristic of the 'freeboard deck'?

It's the deck below which all bulkheads are made watertight, and has permanent means of closing all openings. Signup and view all the answers

Under what condition can a lower deck be designated as the freeboard deck?

If it is a complete and permanent deck continuous in a fore and aft direction at least between the machinery space and peak bulkheads and continuous athwartships AND approved by the Administration. Signup and view all the answers

How is a stepped freeboard deck determined when a recess extends to the sides of the ship?

The lowest line of the exposed deck and its continuation is considered the freeboard deck. Signup and view all the answers

What is the primary focus of the International Convention on Safety of Life at Sea, 1974, concerning passenger ships?

Specifying strict guidelines for the subdivision of passenger ships to control flooding. Signup and view all the answers

What is the fundamental design principle for the spacing of watertight bulkheads in passenger ships in accordance with SOLAS?

Bulkheads should be spaced to confine flooding within reasonable limits when damage occurs. Signup and view all the answers

Why is the spacing of watertight bulkheads critical to passenger safety under SOLAS?

To limit excessive sinkage, trim, or loss of stability in case of damage and flooding. Signup and view all the answers

According to Lloyd’s Register, what is the acceptable range for the location of the collision bulkhead in ships not exceeding 200 meters?

Not less than 5% and not greater than 8% of the ship’s length. Signup and view all the answers

What is the purpose of the aft peak bulkhead?

To ensure that the flooded peak does not cause excessive trim by the stern. Signup and view all the answers

Why are machinery bulkheads important in ship design?

They protect vital components and localize fires. Signup and view all the answers

What is a common factor that would make a classification society recommend additional watertight bulkheads?

When the size of the ship increases. Signup and view all the answers

Under what condition can a ship dispense with one watertight bulkhead?

If adequate approved structural compensation is introduced. Signup and view all the answers

In container ships, how is the spacing of watertight bulkheads often determined?

By the standard length of the containers carried. Signup and view all the answers

Where does the collision bulkhead extend to on a ship?

The uppermost continuous deck. Signup and view all the answers

Why are flat transverse bulkheads typically constructed using horizontal strakes of plating?

To efficiently accommodate the increasing plate thickness at varying depths. Signup and view all the answers

What is the primary reason vertical stiffeners are used on watertight bulkheads, and what advantage do they provide?

They reduce the span, and therefore the tendency to deflect under load, with less material needed for construction. Signup and view all the answers

What factors determine the size of stiffeners used on watertight bulkheads?

The unsupported length, stiffener spacing, and rigidity of the end connections, and the distance between the stringers. Signup and view all the answers

How can horizontal stringers affect the design of vertical stiffeners on a bulkhead?

They reduce the effective span, allowing for the use of smaller stiffeners. Signup and view all the answers

In which direction are swedges or corrugations arranged when used on bulkheads?

Vertically, like conventional stiffeners. Signup and view all the answers

How does the plate thickness of swedged or corrugated bulkheads compare to that of conventional stiffened bulkheads?

It's typically of a uniform thickness, equivalent to that required at the base of the bulkhead. Signup and view all the answers

What is the main drawback of using swedged or corrugated bulkheads, compared to conventional stiffened bulkheads?

They typically result in a heavier plating, offsetting weight savings from not using stiffeners. Signup and view all the answers

What type of end connections may be used for stiffeners in holds?

Either bracketed or simply welded to the tank top or underside of deck. Signup and view all the answers

What is the primary function of swedges in a bulkhead?

To add rigidity to the plate, allowing for the omission of stiffeners. Signup and view all the answers

In which types of vessels are corrugated bulkheads frequently utilized?

Tankers, bulk carriers, and tank spaces of other ships. Signup and view all the answers

What is a common shape for the corrugations in a corrugated bulkhead?

Trapezoidal Signup and view all the answers

What is one of the benefits of using corrugated bulkheads, according to the text?

They can lead to a reduction in welding, and are less susceptible to corrosion. Signup and view all the answers

How are the boundaries of a bulkhead typically secured to the ship's structure?

Double continuously fillet welded directly to the shell, decks, and tank top. Signup and view all the answers

What is the 'shelf plate', fitted to a bulkhead, used for?

To provide a landing point for tween decks when the bulkhead is erected. Signup and view all the answers

What measure is suggested to maintain bulkhead integrity when pipes pass through?

Flanging the pipe at the bulkhead. Signup and view all the answers

What is fitted where a ventilation trunk passes through a watertight bulkhead?

A watertight shutter. Signup and view all the answers

Study Notes

Bulkheads

Bulkheads are vertical partitions in a ship, arranged transversely or fore and aft.
Important bulkheads, including main hull transverse and longitudinal bulkheads, divide the ship into watertight compartments.
Less important "minor bulkheads" subdivide compartments for accommodation or stores.

Watertight Bulkheads

Transverse watertight bulkheads are crucial for:
- Strength: Providing structural support and distributing hull stresses.
- Fire containment: Acting as barriers to prevent fire spread.
- Subdivision: Containing flooding if a compartment is damaged.
The strength of transverse watertight bulkheads is typically equal to the strength of a deck located above the freeboard deck.

Fire Divisions

"H" class divisions resist smoke and flame during hydrocarbon fires for 120 minutes.
"A" class divisions resist smoke and flame during one-hour standard fire tests.
"B" class divisions resist flame for at least half an hour during a standard fire test.
"C" class divisions are built using non-combustible materials.

"A" Class Division

"A" class divisions are formed by bulkheads and decks, made of steel or an equivalent material.
These bulkheads should be suitably stiffened.
They are designed to prevent the passage of smoke and flame during the one-hour standard fire test.
Different "A" classes have different insulation standards, specifying a maximum allowable temperature rise from 0 to 180 degrees Celsius within a certain time period (60, 30, 15, or 0 minutes).

"B" Class Division

"B" class divisions are formed by bulkheads, decks, ceilings, or linings.
They are designed to withstand flame passage for a minimum of the first half hour of the standard fire test.
There are different "B" classes, with specific insulation standards similar to those of "A" classes, though the maximum allowable temperature rise from the original temperature for these classes has an upper limit of 225°C.

"C" Class Division

"C" class divisions are made of approved non-combustible materials.
They do not require any specific fire resistance requirements.

Spacing Of Watertight Bulkheads - Cargo Ships

The minimum number of transverse watertight bulkheads in a dry cargo ship is regulated.
A collision bulkhead is required, located forward, and an after peak bulkhead enclosing the stern tubes should be in a watertight compartment.
A bulkhead should be at either end of the machinery space.
For vessels shorter than 200 m, the collision bulkhead must be between 5% and 8% of the ship's length (Lloyd's Length) from the front edge water line.

Watertight Bulkheads (General)

For vessels with machinery amidships, the minimum watertight bulkheads are four. Machinery aft can reduce this to three.
The minimum number of watertight bulkheads for ships may vary based on the size of the vessel and the requirements of the classification society for subdivision.

Collision Bulkhead

Collision bulkheads are essential to prevent severe damage to ships in collisions.
They are positioned to minimize damage in such events, and their location is often specified as not being too far forward to avoid possible impact damage or too far aft to avoid trim problems.
Lloyd's Register specifies locations for ships under 200 meters.
They are important in preventing flooding and maintain stability.

Watertight Bulkheads (Passenger Ships)

Passenger ships must follow a distinct subdivision setup according to the International Convention on Safety of Life at Sea (SOLAS) from 1974.
The maritime authorities who subscribe to this convention control and dictate the calculations and construction of these ships.
The spacing of bulkheads is crucial to contain flooding if the ship is damaged and is important in preventing ship loss from instability and sinking from flooding.

Construction Of Watertight Bulkheads

The plating of transverse bulkheads is typically welded in horizontal layers. Smaller bulkheads can often be built as single units, but larger ones may require multiple sections.
Plate thickness increases the farther below the top edge of the bulkhead. That's due to water pressure.
Vertical stiffeners support the bulkheads, and their spacing is directly related to their load-bearing capacity.
Bulkhead stiffeners take a variety of shapes, including welded inverted angle bars or offset bulb plates. The shape and size are based on unsupported length and stiffener spacing.
Vertical stiffeners in some situations can be supported by horizontal stringers. This is often seen for tank-defining bulkheads, because of the reduced span, which reduces the load on the stiffeners themselves.

Swedged or Corrugated Bulkheads

Modern ships often feature swedged or corrugated bulkheads, which are built with vertical grooves or ridges.
During construction, the plating for these bulkheads is either swedged or corrugated, which leads to a similar uniform thickness throughout the bulkhead. The plate thickness can thus be optimized for strength, which avoids the need for extra stiffeners. This can be made more efficient with corrugated plate.
These can be constructed with savings compared to conventional bulkheads.

Corrugated Bulkheads

Tank spaces of ships, especially tankers, sometimes use corrugated bulkheads with trapezoidal shapes.
these bulkheads offer savings in welding costs. Also, they allow for easier tank cleaning and cargo flow.
The angle and depth of the corrugations are critical specifications for performance and strength

Boundaries of the Bulkheads

The edges of bulkheads are typically continuously welded to the hull, decks, and tank tops.

Fitting of Decks to a Bulkhead

Bulkheads are sometimes built first, and then decks are fitted over them, using plate welding that extends out a few centimeters.

Pipes through Bulkheads

In corrugated bulkheads, filler pieces are sometimes needed along the shell plating in locations where pipes pass through the bulkhead.
To ensure watertightness, pipes are frequently avoided in watertight bulkheads.
Alternatively, pipe penetrations in bulkheads can be fitted with watertight seals or flanges.

Testing Watertight Bulkheads

Testing methods often involve filling specific compartments (fore peak, aft peak) with water to assess the system's watertight capability.
Hose testing is also involved to verify the leakproof integrity of the bulkhead, especially for bulkheads that are not water-filled.

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Description

Test your knowledge on marine fire safety regulations, including temperature limits for fire divisions and bulkhead requirements in dry cargo ships. This quiz covers various classes of divisions, their characteristics, and mandatory safety features. Perfect for maritime professionals and students in marine safety fields.