Scaffold types

Student Booklet © Ministry of Education. December 2009. The material was developed for Continuing Education Committee for the building / construction industry and in cooperation with lecturer Ole Østergaard Nielsen, AMU West. The material can freely be further worked with the following text: "This material contains a processing of the material "Pipe and industrial scaffolding - Pupil Booklet" in December 2009 developed for the Ministry of Education After building / construction industry and in collaboration with Ole Østergaard Nielsen, AMU West 1

Scaffold types

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Scaffold types Content Different scaffold types ..................................................................................................................................... 5 Double pillared scaffold ............................................................................................... 5 Safety checks for double pillared scaffolds .................................................................. 6 Every night: ............................................................................................................ 6 Safety measures ...................................................................................................... 6 Setup ..................................................................................................................... 8 Diagonals................................................................................................................ 9 Pipes as riding bars .................................................................................................. 9 Work platform ....................................................................................................... 10 Dangers ................................................................................................................ 11 Spacious scaffolds .................................................................................................... 14 Scaffold measurements .......................................................................................... 14 Diagonals.............................................................................................................. 15 Length pipes, joists and couplers ............................................................................. 16 Attachment ........................................................................................................... 16 Foundation ............................................................................................................ 16 Work platform ....................................................................................................... 16 Access points ........................................................................................................ 16 Setup instructions .................................................................................................. 17 Annexes .................................................................................................................. 21

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Scaffold types

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Scaffold types Different scaffold types Double pillared scaffold

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Scaffold types Anchored scaffolds with double pillared rows is the most common type of scaffold used. It consists of two rows of pillars set up parallell to the building, joined by length pipes, whcih are attached by right anglesd couplers. The joists are attached in a right angle onto the length pipes with joist couplers. The inner row of pillars is placed as close to the building as possible. Most double pillares scaffolds have 4 or 5 scaffold boards placed in between the pillars. An konsol without underpinning may only be addedd to the one side of the scaffold and may not exceed 0,30 m. Remember to secure scaffold decks.

Safety checks for double pillared scaffolds Every night: • ladders must be secured in a way that does not permit unauthorized people to entry the scaffold • the scaffold shoul be lit to protect from accidents. E.g. traffic • check that warning signs and lamps are in place. Every morning: •

make sure that the scaffold has not had any accidents or been exposed to vandalism and is safe to use. Every week: •

the scaffold should be inspected once a week by a skilled person, and it must always be inspected after a storm. Before taking the scaffold down: •

the order in which the scaffold is taken down is not necessarily the reverse order of setup. Generally scaffolds should be taken down story by story, and not from one end to the other.

Safety measures When setting up and taking down a scaffold, necessary precautions must be taken. Helmet, safety foot wear and possibly gloves must be used. If there is a risk of falling down during the work on the scaffold, fall protection gear must be used. Remember therefore to always wear fall protection gear during scaffold work to avoid unnecessary chances.

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Scaffold types Scaffolds with single pillar rows

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Scaffold types Scaffolds of pipes and couplers with single pillar rows are mainly used in connection with brick work. The scaffold consist of one row of pillars placed parallell to the building. The pillars are joined with length pipes, which are attached with right angled couplers, and the joists are attaches to the length pipes either with right angled couplers or joist couplers. A joist in a single pillared scaffold is a piece of pipe which is flat like a plate at the one end. When the plate supports in the brick work of the building, it must be considered in every case that the pressure on the wall does not exceed the alloved tension of the respective brick work. Just as the other materials of the scaffold should not exceed their respective limits. These tensions should be calculated by presupposing that the underpinning plate is put 1 cm less into the wall that it theoretically could. Setup Pillars Pillars must be places on base plates, that have been placed on pressure equalizors. The distance between each pillar may not exceed the values mentioned in table 1. The lift is normally 1,40 m. Anchorings Caution must be paid to the scenario that the brick work is not completely hardened and that work on the scaffold may not proceed until the brick work is able to carry the strains put on it. The requirements of anchoring is descibed in a different section.

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Scaffold types Diagonals Facade diagonals should be attached normally. Cross- or length pipe diagonals are not stricktly permitted, however, it is advised to mount a length pipe diagonal to every third pillar, as shown. Pipes as riding bars When passing by widow- or door openings it is necessary to mount a pipe to the underside of the joists. This pipe functions as underpinning for the joist, which are not supprted by any brick work. The pipe should be attached by right angled couplers. Pipes that function as riding bars also dunction as the inner most attachment point for diagonals.

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Scaffold types Work platform The width requirements of a work platform depend on the kid of work performed.However, as a minimum, there should be a clearance space of 60 cm. When there is a risk of falling objects, there should be additional shielding installed; e.g. box shields, nets or similar. Examples of shielding

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Scaffold types Dangers Some of the most common dangers of single pillared scaffolds are: •

the underground may be undermined by a differnt work, or the scaffold may be placed on filled digs. • the work platform may be overloaded or the bricks are stacked higher than the net. • the railing is removed due to other work and has not been reattached. • tor recesses have been removed. • missing scaffold boards. • anchorings have been removed. • diagonals have been removed. Setup instructions: •

1. Raise the pillar on a base plate, which has been placed on a pressure equalizor, and attach the first joist to the pillar using a right angled coupler.

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2. Attach the second pillar and joist as before.

•

3. Attach length pipes below the joists. The construction is temporarily stabilized with cross pipes.

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Scaffold types •

4. Place the start lift about 150 mm above the base plates - comepletely level.

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5. Attach a pipe tp the undersde of the joists in a distance of about 100 mm from the wall. Mount the diagonals. Length pipe diagonals must be attached to the pipe, which has been mounted below the joists and lead down to the start lift, and at the same time a facade diagonal should be mounted.

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6. The scaffold is finished by mounting intermidiate joists, work platform and railings.

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Scaffold types Safety inspections for single pillared scaffolds:

Before • • • •

setup: all bricks have been removed and the foundation is level. filled digs have been compressed. the scaffold worker is aware of the whereabouts of the filled digs, or is aware of the whereabouts of any future foundation work.

After building the first lift: • that pillars are virtical and placed safely on base plates and pressure equalizors. • that length pipes are horizontal and attached to the pillars with well greased and inspected couplers. • that the joists are placed safely in the joints or that they are resting safely on the brick work. • that the joists are horizontal and mounted onto the length pipes (the main joists with a distance to every pillar of max 300 mm) • pipes that function as riding bars are joined with the joists by right angled couplers. • the scaffold boards are close, safely supported and that the distance to the wall is according to the requirements. • that the railing has been mounted. • secure access points have been established. • secure that the brick layer and the crane worker are aware of the maximum weight the scaffold can be burdened with. After bulding the second lift and before loading the scaffold: • that anchorings have been mounted in hardened brickwork. • that the joist ends still are in place in the joints at first lift height. There is a tendency that the scaffold may move away from the wall once the second lift’s joists are mounted. During work, the follwoing must be secured: • that the scaffold is not overloaded, • that nets or box shields are in place, • unused access points are secured with railing, • every damage that has come about during the works (truck, crane etc.) must be repaired instantly • that no scaffold board are removed from the work platform • that the ends of the scaffold are secured with railing and anchorings.

When taking down the scaffold, make sure that railings are mounted, and that scaffold boars have been placed for the brick layer to stand in while he repairs the holes in the wall caused by the joists.

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Scaffold types Spacious scaffolds A spacious scaffold consist of a row of parallell pillars placed at regular intervals. These pillars are connected to a net of length pipes and joists at every lift. On the last lift, scaffold boards are placed to make a work platform. Scaffold measurements Setup instructions for steel pipe and coupler scaffolds with scaffold decks. The mentioned distances are measured from the middle of a pillar to the middle of the next pillar. Table 12 Pillar distance for length pipes in the width (w) in metres max.

Pillar distance for the length (L) in metres max.

1

1,75

2,50

2

1,50

2,25

3

1,50

2,00

4

1,00

1,75

5 and 6

0,75

1,75

Scaffold category

Table 12

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Scaffold types Spacious scaffolds must have the prescribed pillar distance as mentioned in table 12. At setup in the open air: • the relation between the top scaffold deck and the middle sideline may not exceed 3:1 • the height to the top scaffold deck may not exceed 12 m • the horizontal distance between the length- and the cross pipes may not exceed 2 m. At setup in closed spaces: • • •

the relation between the top scaffold deck and the middle sideline may not exceed 4:1 the height to the top scaffold deck may not exceed 20 m the horizontal distance between the length- and the cross pipes may not exceed 2 m.

Diagonals The diagonals should be attached from length pipe to length pipe with right angled couplers or to the pillars with swiwel couplers. Diagonals should be placed at every other pillar row in the length- and cross direction. (illustration below)

Horizontal diagonals should be mounted to every other centre.

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Scaffold types Length pipes, joists and couplers Length pipes and joists chould be attached to the pillars and to each other with right angled couplers. On work platforms it is alloved to attach the joists with joist couplers, so that the scaffold boards can be placed on a level base. Attachment Attachment is notmally done by holding extra length pipes and joists against the walls. It is necessary to put pie end protectors on the pipes to protect the walls from destruction. Foundation Great considerations should be taken to the foundation when scaffolds are placed on polished wooden floors, marble floors or similar. It may be necessary to place a protective layer underneeth the base plates. Work platform The work platform must be closed tight with scaffold boards, and if 3,90 m scaffold boards are being used, these should be supported by at least 4 joists. Railing should be mounted to the inside of the pillars. Access points The access point is normally placed in the one corner of the scaffold, and as a means of entry, a ladder is usually used.

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Scaffold types Setup instructions There are two main ways of setting up a spacious scaffold. The first: the start lift is mounted around the scaffold in two lengths width, at about 150 mm from the ground. The start lift is attached to the pillars in every of the four corners, followed by length- and cross pipes on the first lift. Intermediate pillars and diagonals can be placed hereafter. 1. Raise the pillars in every corner and connect these with the start lift.

2. Place the length- and cross pipes on the first lift.

3. Mount the intermediate pillars, length- and cross pipes.

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Scaffold types

4. Attache facade diagonals in every corner.

5. Mount the middle pillar.

6. Place the intermediate joists.

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Scaffold types 9. Place the lenght- and cross pipes for the second lift.

10. Continue the zig-zag pattern of the facade diagonals.

11. This mehtod is repeated until the scaffold has reach the required height. Scaffold boards are places a work platfrom and railings (hand railing, middle (knee) railing and toe recess) is mounted. Using the alternative contruction model, the start lift may be left out if the scaffold is more than one lift tall. The start lift is only mounted at the start, and the pipes from here can be used in the following stories.

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Scaffold types Suspended scaffolds A suspended scaffold is a scaffold that is hung from a point, e.g. an I or H beam. It must be secured that the construction can carry the strains that are being put on it. Note 1. Remember that the top coupler is carrying both the top and the bottom platform. “X” marks the spot for safety- or extra couplers to be placed. When extending pipes, sleeve couplers may not be used. A suspended scaffold is assembled by using right angles couplers, also for the joists that support the boards. Suitable diagonals should be used to counteract the movements in either direction.

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Scaffold types

Annexes Free flowing weight-carrying platform.

All measurements are in millimetres. “X” marks the spot for safety- or extra weight-carrying couplers.

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Scaffold types

Konsol is the term used for all extra things that are hung on the side of a scaffold. This may be a hoist, corbels, shields etc. When annexes are installed one must make sure that the anchoring of the scaffold is performed correctly. Diagonals must be placed at every pillar of the annex in the scaffold, and the forced from here should be diverted to the scaffold’s base. The diagonals of the annex should be as close to every pillar as possible and the angle of these may not exceed 35o. Safety couplers should also be mounted. An annex without underpinning may only be added to the one side of the scaffold and may not exceed 0,30 m. The distance between the deck and the annex may not exceed 0,025 m. This distance is however not acceptable for e.g. offshore installments.

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Scaffold types

Superstructure In the following illustration it is shoen how a superstructure with a scaffold height of up to 20 m may be installed. Below the superstructure’s fixture, double pillars must be used. At scaffold height shorter than 8 m, single pillars may be used, if the scaffold pipes have a material thickness is 4,0 mm. For a superstructure it is also alloved to use grid girders.

The superstructure is made from pipe- and coupler scaffolds of steel.

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Scaffold types Scaffold types, assignment number 1 1. What is the max size of an annex without underpinning?

2. How can a suspended scaffold be extended downwards?

3. What is the pillar distance for length pipes and cross pipes respectively in a spacious scaffold (category 3)?

4. May a sleeve coupler be used to extend a pipe in a suspended scaffold?

5. What is the relation between the top scaffold deck and the middle sideline for a specious scaffold set up in open air?

6. What is the maximum angle of a diagonal in an annex?

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Scaffold types

7. How many pillars must be used under a superstructures fixture?

8. What does a spacious scaffold mean?

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