PVR and technological card for erecting masts and poles: what they contain and what to hand to the erector

Who does what and where our part ends

Erection of a mast or pole is done by our partner construction company; POLYGONAL has no erection crews of its own. The PVR and the technological cards are prepared by that company: under the standard the work execution project is developed by the construction organization for the types and stages of work it carries out, and for complex work design or research organizations can be brought in.

Our part comes before the PVR. We fabricate the structures, prepare KM and KMD drawings and pass on the data the PVR is built on: the mass and centre of gravity of the marks, the section assembly scheme, the slinging points, the class and tightening torque of fasteners, the anchor assembly. The customer or the customer’s designer supplies the rest: the construction organization project (POB), with which the PVR must be consistent, site conditions and foundation data.

The article explains what these documents are and what is worth agreeing with our side before fabrication, rather than after the crane has already been ordered.

PVR and technological card: what is the difference

A PVR is prepared for a facility, a phase of it or a separate stage of work. Under DBN A.3.1-5:2016 it contains the decisions on the technology and organization of the work and a list of the required as-built documentation, is based on the working documentation and the POB, and takes into account the characteristics of the structures, the machines involved and the conditions of work. A technological card (TC) is prepared for one type of work: it sets out by operation who does what, with which equipment, in what sequence, and how quality is checked.

The standard allows both options: construction work is carried out on the basis of the PVR and/or technological cards. How many documents are needed and how detailed they are depends on the volume and complexity of the work, the degree of mechanization, the complexity category of the facility and the responsibility category of the structures. In practice one low pole may need only a TC with a short scheme, while a 30–42 m mast, a portal with a crossbeam or several poles on several work sections need a full PVR with crane position, slinging and bracing schemes.

There are also standard technological cards. The standard allows relevant typical documentation to be used, but such a card knows neither the mass of your section nor the boom radius on your site, so it is tied to the specific structure and crane.

The PVR composition is given by the reference appendix K of DBN A.3.1-5:2016. The standard calls it indicative: the list and level of detail depend on the facility.

Why erection does not start without a PVR

The requirement follows from several rules at once. DBN A.3.2-2-2009 requires safety measures to be stated in the design and technology documentation (POB and PVR) and prohibits construction and erection work without a PVR. The occupational safety rules for cranes (NPAOP 0.00-1.80-18) require crane work to be run under a PVR or technological cards approved by the employer; the responsible person, crane operators and slingers are made familiar with them against signature.

The rules for work at height (NPAOP 0.00-1.15-07) link the PVR to the work permit: a PVR or technological cards are attached to the permit at the decision of the persons who issue permits.

For the customer this comes down to something simple: without a PVR the erector will not get a permit for work at height and will not put the crane in place. So the question «is there a PVR and who prepares it» is settled in the contract with the erection company while the structures are still being fabricated.

PVR composition for erecting a mast or pole

The table lists PVR components under appendix K of DBN A.3.1-5:2016 and what matters in each of them specifically for a mast or pole. The third column shows where the input data come from.

For separate erection works the standard shortens the composition to five items: calendar schedule, construction site plan, technological card or scheme of execution, demand for materials, structures, machines and equipment, and an explanatory note.

What a PVR for one mast looks like

A set for one mast of three sections with a crown usually consists of several sheets:

• general data and a list of referenced documents;
• an erection site plan with the crane position, storage and assembly areas, fencing of the danger zone, anchors for winches and guys, a schedule of erection marks with masses and a list of machines, equipment and slings;
• an erection scheme for the work section;
• a section with instructions on preparatory work and sequence;
• a section with temporary bracing;
• a section on crown erection with safety instructions;
• a slinging scheme for each mark and the load charts of the crane.

Preparatory work in such a set is named directly: the foundation is concreted and accepted by an act, backfilling is done, the assembly area and a crane position with a base that carries its load are arranged, blocks for guys and winches are installed, the danger zone is fenced, and the equipment is checked. The order then follows: assembling sections on the ground, setting on the anchor bolts with the crane and temporary bracing, the crown with equipment, removing the guys after final fixing.

What a technological card for assembling and erecting a pole contains

A card for a multisided pole usually has these blocks: crew composition with grades and safety groups, machinery, equipment (hydraulic jacks with a pump unit for clamping sections), protective equipment, accessories (slings, links, shackles, ropes), instruments (theodolite, radios), tools, materials with the mass of each section and the number of fasteners, and then a table of operations. Each row of the table is an operation, a performer and a number of people.

For poles with a telescopic joint the card spells out the following (numerical parameters are taken from the fabricator’s instruction, not from the card of a neighbouring site):

• sections are laid out near the foundation on trestles or supports levelled horizontally, with timber packing under the section;
• before assembly the welds and the joint surface are inspected; shells, runs and dents are removed, and if that fails the element is replaced;
• the clamping limit is marked on the sections, and axis marks on the faces and flanges: for angle poles they run along the bisector of the line angle;
• sections are clamped by jacks in steps, recording the joint length at each step and watching the pressure; if the end has not reached the mark and the force is not released, the joint is tapped through a timber pad, but not on the welds;
• clamping ends when the joint reaches the mark or stops shortening; the clamping device is then removed and the next section is dealt with;
• crossarms, brackets, ladders and platforms are installed, the tightening of assembly bolts is checked, and the pole number and type are marked.

The force, load step, permitted joint length and marks are set by the fabricator. In our recommendations for assembling a telescopic joint the clamping load is at least 10 t, and the tolerance on joint length is stated in the design documentation and is usually 10–12 % of the joint length; more in the article on assembly and erection of multisided poles.

What the fabricator hands to the erector

The erection company transfers the data in the table into the PVR. If something from the list is missing, the author takes a value from a similar project or waits for an answer, and either way the lifting schedule suffers.

Trial assembly in the shop

Trial assembly of joints, including flanged pairs of sections, is done by us in the shop if it is in the request. Then flange mismatches are found before dispatch, not on site when the crane is already standing. For the checks themselves at the factory and on site, see the article on acceptance of multisided poles.

Temporary bracing and stability during erection

A column set on the anchors holds on the nuts and slings until it is finally fixed. In our recommendations the slings are removed only after all nuts on the foundation are fully tightened, and before that the pole is aligned. But erection of a mast does not end there: the crown still has to be lifted, and the column already stands without slings.

So a PVR often provides temporary bracing with guys to anchors, for example three guys spread at 120° in plan. The number, angle, anchors and the attachment on the column must be given by the PVR, and the guys are removed after the crown is installed and fixed.

The attachment of guys to a thin-walled column is worth agreeing with the fabricator. Clamping at an arbitrary section can crush the wall of a polygonal shaft, so the place and method (lugs, pad, collar) are checked by calculation, not chosen on site. The same applies to the telescopic joint: during lifting the sections must not slide apart, so the joint is slung in a special way or locked at the lugs with temporary devices that are removed after the lift.

The crown is a case of its own. It is lifted last and is the operation most sensitive to wind: more in the article on floodlight masts 30–42 m. The mass of the crown with floodlights and the method of seating it on the flange belong to the slinging scheme and are not decided on site.

Safety: danger zone, crane, work at height

NPAOP 0.00-1.80-18 names what a PVR for crane work must provide: crane positions with marked working and danger zones and measures to limit them, suitability of the crane for the work by capacity, height and radius, safe distances to live parts and power lines, to buildings and storage places, conditions of joint operation of several cranes, lists and masses of loads, removable lifting accessories and slinging schemes, storage places and dimensions, walkways and access roads, safety measures on the site (fencing, lighting in the dark).

Slinging schemes are issued to slingers and operators and posted at the work places. The limiting wind speed for a crane is given in its passport: above that speed work is prohibited.

Work at height has its own limits. The rules do not allow such work in open places at a wind speed of 10 m/s or more, in icing, thunderstorm or fog that reduces visibility across the work front, nor at night with insufficient lighting, nor at an air temperature above plus 35 °C or below minus 20 °C. Urgent work in worse conditions is allowed at the employer’s decision, but the additional safety measures must be written into the PVR.

The first lift is made to a small height to check the slinging and the brakes: in our recommendations this is 200–300 mm (slinging of steel structures). Climbing the pole, ladders and fall-protection systems are covered in the article on fall-protection systems and ladders.

Foundation, anchors and surveying before the crane arrives

A PVR starts not with the crane but with an accepted foundation. Appendix N of DBN A.3.1-5:2016 lists, among the works accepted by an act before subsequent work, the preparation of bearing places and fixing of steel structures on foundations, including a survey check of the actual position in plan and elevation and an as-built scheme; embedded parts installation is a separate item. For a pole this means: every anchor bolt is measured, the result is recorded on the as-built scheme, and a deviation is corrected before the pole arrives, not by forcing the flange.

Before lifting, the below-ground works must also be complete, the foundation aligned in level and pole axis, and the concrete must have reached at least 50 % strength, as in our recommendations, or more if the design says so. We do a foundation design as a separate order for a separate fee, and often only pass on the loads; more in the article on inputs for foundation design.

Surveying decisions are part of the PVR too: schemes for placing marks, requirements for accuracy and control means. Plumb of the pole is measured in two perpendicular directions before the slings are removed, while it can still be adjusted with the levelling nuts. The permitted deviation is set by the design, and we do not give numbers in the articles.

Orientation also belongs to the PVR: the position of the door, ladder and brackets relative to the site plan or the line axis is taken from the design, not chosen at lifting. For this the marks on the flange and the foundation are made in advance. About anchors and cages: anchor bolts and foundation anchor cages.

Control, acts and as-built documentation

DBN A.3.1-5:2016 divides production control into four parts: incoming control of design documentation, incoming control of structures, products and materials, operational control of construction processes, and acceptance control. For a pole this means the following.

• incoming control of structures: conformity with the design, passports and certificates is checked, marking and completeness are verified; it is better to record remarks at unloading, not after erection;
• operational control: its scope and parameters are set by the PVR, and results are entered in the general work log; all deviations are corrected before the next technologically related operations begin;
• acceptance control: concealed works and critical structures are accepted by acts before subsequent work, with representatives of the construction organization and the customer’s technical supervision, and by contract also the designer’s supervision.

The list of required as-built documentation must be given in the PVR itself: the general and special work logs, acts for concealed work, interim acceptance acts for critical structures, as-built schemes, laboratory control documents. What to ask from us together with the product is described in the article on acceptance of poles, and what to send the fabricator before production in the article on the document package for the fabricator.

Where mistakes are most common

• a PVR or card from another site: section masses, radius and joint design differ, while the document holds someone else’s numbers;
• the crane is chosen by the mass of black steel, and the mass of zinc, fasteners, ladders and crown is not added;
• the PVR was prepared from an old edition of the KMD: after drawing changes the mass and centre of gravity changed, and the slinging scheme was not recalculated;
• slinging by bolt holes or by the flange, which is designed for wind and not for lifting, and bare ropes on zinc;
• no allowance for the telescopic joint sliding apart during lifting;
• the pole was unslung before all nuts on the foundation were tightened;
• guys are in place, but their attachment to the thin wall has not been agreed with anyone;
• for the crown lift there is no wind limit and no action plan if the wind picks up;
• tightening torque and re-tightening order were changed on site without agreement with the fabricator, and galvanized joints were not re-tightened;
• the orientation of the door and ladder is not marked on the foundation: the pole is lifted and then turned.

What to agree before ordering and what to hand to the erector

Before fabrication starts, decide who prepares the PVR (the erection company, the general contractor or the customer) and how the fabricator passes data to them. Then the assembly instruction, mass, centre of gravity and slinging scheme get into the PVR from the first edition, not the third.

• lifting method: one crane, two cranes, or a crane with winches; lugs, guy lugs and temporary devices on the joint depend on it;
• slinging points, lugs and the design mass on them;
• assembly instruction and erection scheme, especially for a telescopic joint;
• fastener schedule, tightening torque and re-tightening order;
• loading scheme and the order in which marks arrive on site;
• orientation of the door, ladder and brackets on the plan;
• documents accompanying the product, and whether trial assembly in the shop is needed;
• who repairs the coating after erection: we do not do this.

Fabrication of steel structures to the customer’s drawings and KM/KMD design are our service lines: KM and KMD design, steel fabrication. We supply fasteners for the connections together with the structures. Erection, and the PVR with it, is done by our partner construction company. For switchyard portals see portal erection, for telecom towers and masts telecom towers. What else to send for the calculation is in the article How to order poles and masts.

Standards and validity

The composition and content of a PVR, the division between the PVR and technological cards, as-built documentation and quality control are set out in DBN A.3.1-5:2016 «Organization of construction production» (in force from 01.01.2017, replaced the 2009 edition). According to open data the standard is current, but one card of the state register e-construction marks it as archived, so its status is checked before it is cited in documents. Used: cl. 4.8, 5.3.1–5.3.5, section 8, appendices K and N.

Occupational safety in construction is covered by DBN A.3.2-2-2009 «Occupational safety and industrial safety in construction. Basic provisions» (current by the state register; amended by orders of 2010 and 2011; section 4 on safety measures in the POB and PVR was used). Requirements for a PVR for crane work and slinging schemes are in NPAOP 0.00-1.80-18 «Occupational safety rules for the operation of cranes, lifting devices and related equipment» (order of the Ministry of Social Policy of 19.01.2018 No. 62, registered with the Ministry of Justice on 27.02.2018 under No. 244/31696, in force from 10.04.2018, no amendments found; section VII, chapter 2, cl. 12–14, chapter 4, cl. 16). Work at height is covered by NPAOP 0.00-1.15-07 «Occupational safety rules for work at height» (order of the State Committee for Industrial Safety of 27.03.2007 No. 62, registered on 04.06.2007 under No. 573/13840, in force; cl. 1.7 and 1.16).

Surveying and as-built schemes fall under DBN V.1.3-2:2010 «Surveying works in construction» (current by the state register, with Amendment No. 1). This is a summary of requirements for orientation, not a project: the PVR and technological cards are prepared by the organization that does the erection, and wind limits, distances and numbers in them are taken from the current edition of the rules and the crane passport. Check the validity of every document before citing it in a project.