NB/T 20358.1-2018Cost estimation of nuclear power plant construction project - Part 1: Civil engineering for nuclear island (English PDF)

Foreword

This document was issued on 22 March 2018 by the National Energy Administration of the PRC and takes effect on 1 September 2018.

It is a NB/T standard: recommended rather than compulsory, but it is the text a Chinese reviewer applies when assessing a submission.

It is classified under ICS 01.040.27, Chinese classification F02.

It replaces NB/T 20358.1-2015, which is superseded.

NB/T 20358 Budgetary Cost Quota for Nuclear Power Plant Construction Projects, together with NB/T 20355 Cost Quota for Civil and Erection Works of the Nuclear Island of Nuclear Power Plant Construction Projects, NB/T 20356 Cost Quota for Civil and Erection Works of the Conventional Island of Nuclear Power Plant Construction Projects and NB/T 20357 Machine-Shift Cost Quota for Nuclear Power Plant Construction Projects, makes up the series of nuclear power quota standards that supports the budgeting and pricing of nuclear power construction projects.

NB/T 20358 Budgetary Cost Quota for Nuclear Power Plant Construction Projects currently comprises 16 parts, composed as follows:

Part 1: Civil engineering for the nuclear island.

Part 2: Decoration works for the nuclear island.

Part 3: Steel structure works for the nuclear island.

Part 4: Installation of process equipment for the nuclear island.

Part 5: Installation of process piping for the nuclear island.

Part 6: Installation of ventilation and air conditioning for the nuclear island.

Part 7: Installation of electrical equipment for the nuclear island.

Part 8: Installation of automation control instrumentation for the nuclear island.

Part 9: Installation of communication equipment for the nuclear island.

Part 10: Anticorrosion and thermal insulation works for the nuclear island.

Part 11: Civil engineering for the conventional island.

Part 12: Installation of thermal (steam-cycle) equipment for the conventional island.

Part 13: Installation of electrical equipment for the conventional island.

Part 14: Commissioning works.

Part 15: Fabrication of modules and of the steel containment.

Part 16: Assembly and installation of modules and of the steel containment.

This part is Part 1 of NB/T 20358.1-2018 Budgetary Cost Quota for Nuclear Power Plant Construction Projects, namely Civil Engineering for the Nuclear Island (hereinafter called this quota). It was released by Announcement No. 2 of 2018 of the National Energy Administration, approved on 22 March 2018 and put into effect on 1 September 2018.

This part was proposed by the Nuclear Power Standardization Technical Committee of the energy industry.

This part is under the jurisdiction of the Nuclear Industry Standardization Research Institute.

Main drafting organizations of this part: China Nuclear Power Engineering Co., Ltd.; China General Nuclear Power Engineering Co., Ltd.; Electric Power Planning and Engineering Institute; China Nuclear Industry 23rd Construction Co., Ltd.; China Nuclear Industry Huaxing Construction Co., Ltd.; China Nuclear Industry 22nd Construction Co., Ltd.

Main drafters of this part: Wang Fang, Zhao Yang, Chi Jing, Han Zhaoxing, He Li, Zhao Dong, Yu Yang, Kong Liang, Huang Wenxiu, Hu Qingyun, Wu Mei, Liu Shihong and Wu Ziyu.

Volume Description - 1 Scope

This quota lays down the nuclear island civil engineering quota within the budgetary cost quota for nuclear power plant construction projects.

This quota applies to the nuclear island works of new-build and extension projects of pressurized water reactor nuclear power units, and to those sub-items of the balance-of-plant (BOP) works that carry nuclear safety requirements, such as the nuclear island liquid waste storage tank building, the conventional island liquid waste storage tank building, the auxiliary building for the treatment of radioactive solid waste, the interim storage facility for solid waste, and the radioactive machinery repair and decontamination workshop. Other reactor types and nuclear projects may use it for reference.

Volume Description - 2 General Provisions

1. This quota shall be applied in conjunction with the Cost Quota for Civil and Erection Works of the Nuclear Island of Nuclear Power Plant Construction Projects and the Machine-Shift Cost Quota for Nuclear Power Plant Construction Projects.

2. This quota is the basis for preparing construction-drawing budgets, for engineering fund appropriation and completion settlement, for tendering and bidding, and for bill-of-quantities pricing; it is also the basis on which the preliminary estimate quota is compiled.

3. This quota has been compiled on the basis of normal natural and environmental conditions, of a construction organization design and construction plant allocation that are reasonable for the present stage, of reasonable cross-operation, and of the relevant technical standards of pressurized water reactor nuclear power plants, the construction and acceptance codes, the quality outlines and safe operating procedures, and the requirements for civilized and safe site construction and for environmental protection.

4. The labour, material and construction machinery consumption figures in this quota reflect the technical and organizational level of nuclear power plant construction at the present stage. Except where the quota expressly permits adjustment, the quota shall not be adjusted on account of differences in construction organization, operating method or material wastage.

5. The determination of labour cost in this quota is laid down as follows:

5.1) Labour in this quota is expressed in composite work-days, without distinction of trade or skill grade, each composite work-day being counted on the basis of an eight-hour working day.

5.2) The composite unit price of this quota is applied at a production worker wage of 120 yuan per work-day, which includes basic wages, wage subsidies, auxiliary wages, employee welfare expenses and labour protection expenses.

6. The determination of material consumption in this quota is laid down as follows:

6.1) The materials (semi-finished and finished products) in this quota are taken as conforming products that meet the quality standards and the design requirements and that carry certificates of conformity and test records.

6.2) The quantities of materials (semi-finished and finished products) in this quota all include the losses arising from transport within the site, from construction operations and from stacking on the construction site.

6.3) Turnover (reusable) materials are entered at the turnover amortization amount.

6.4) Sundry materials of small quantity and low value are combined in this quota into an item of other material cost, expressed in yuan.

6.5) Material costs are taken uniformly at material warehouse prices; the freight miscellaneous charges, the transport loss and the procurement-and-custody rate together amount to 2.5 percent.

7. The determination of construction machinery consumption in this quota is laid down as follows:

7.1) The types and specifications of the building plant in this quota have been determined comprehensively for normal construction and reasonable allocation, taking account of the way in which nuclear industry construction enterprises are equipped with machinery. In execution, unless the quota states otherwise or the design carries special requirements, no arbitrary adjustment shall be made merely because the machinery actually used differs from that in the quota.

7.2) The amortization of small construction machinery is combined in the quota into an item of other machinery cost, expressed in yuan.

7.3) The quota already includes the labour and machinery consumption needed for the horizontal and vertical transport of materials, semi-finished products and finished products from the site warehouse, the site stacking point or the site processing point to the point of operation.

7.4) Materials, finished products and semi-finished products shall be stacked at the positions laid down in the construction organization design. Since the construction site of a nuclear power plant construction project is for the most part formed by blasting and excavating earth and rock and the site is compact, the ground that can be laid out for stacking materials, finished products and semi-finished products is very limited, so that secondary or repeated re-handling is unavoidable; the corresponding cost is charged under the secondary handling item of the civil and erection works cost quota.

8. The work content of this quota states the main construction operations; the secondary operations, although not stated, are all taken as included in the quota.

9. Where this quota is marked within XX or XX and below, the value XX itself is included; where it is marked beyond XX or XX and above, the value XX itself is not included.

10. This quota is based on construction under normal climatic, geographical and environmental conditions and does not take account of the factors of construction under special winter, rainy-season, night-time, high-temperature, severe-cold or harmful conditions. Where construction in a special environment causes a loss of construction efficiency, the additional cost shall be reported separately by the construction unit and charged separately.

11. Matters not exhausted by this description are set out in the explanations to the individual chapters.

1 Scope

NB/T 20358.1-2018 is Part 1 of the Chinese budget quota series for nuclear power plant construction, and as the opening volume it carries both the general rules that govern the whole series and the unit rates for civil engineering in the nuclear island. The general explanation at the front is the part an estimator must read before using any volume: it sets the scope of the quotas, what each rate already includes and excludes, the adjustment coefficients applied for working conditions, the material waste allowances, and the rules for measuring quantities. The civil work itself follows: site clearance and earthworks, rock excavation including controlled and smooth blasting with the geometry rules that decide which rate applies, backfill and compaction, dewatering, foundation preparation, formwork of all classes, reinforcement fixing, concrete placing for the heavy raft and the containment structures, embedded parts and liner plates, masonry, and the finishes. Each quota item gives the work content, the unit of measurement, the labour hours by trade, the machine-shift consumption by equipment type and the material quantities. It replaces the 2015 edition. Because it holds the general provisions, this part is used alongside every other volume in the series by owners, contractors and cost consultants preparing budget estimates, tender prices and cost control baselines for nuclear power projects in China.

1. Soil classification is given in Table 2. Classes I and II of that table are the Class I-II soil (ordinary soil) of the quota; Class III is the Class III soil (hard soil) of the quota; Class IV is the Class IV soil (gravelly hard soil) of the quota. The quota depth for manual excavation of trenches and of pits is at most 4 m; where 4 m is exceeded, a supplementary quota may be prepared.

2. The manual earthwork and rockwork quota has been compiled for dry soil; where wet soil is excavated, the labour is multiplied by a factor of 1.18. The division between dry and wet soil shall be drawn from the geological investigation data taking the normal underground water level as the boundary: above the underground normal water level the soil is dry, below it the soil is wet.

3. This quota does not include the dewatering cost for construction below the groundwater table; where dewatering occurs it is calculated separately. Where surface water has to be drained during earth excavation, this too is calculated separately.

4. The sheeting (retaining board) quota items are divided into close sheeting and spaced sheeting. Close sheeting means retaining boards placed in full contact; spaced sheeting means retaining boards placed at intervals. Where the actual spacing differs, the quota is not adjusted.

5. Where earth is excavated with the support of retaining boards, the actual excavated volume is taken and the labour is multiplied by a factor of 1.43.

6. Where earth is excavated and filled vertically within the site, the quantity for site levelling is not calculated again.

7. The haul distance for borrowed backfill earth is provisionally taken as 3 km; where 3 km is exceeded, the additional cost is charged separately at the earth haulage unit price.

1 Chapter 1 - Chapter Explanation, Mechanized Earthwork and Rockwork

1. Rock classification is given in Table 2. Class V of that table is the soft rock of the quota; Classes VI to VIII are the medium-hard rock of the quota; Classes IX and X are the ordinary hard rock of the quota; Classes XI to XVI are the extra-hard rock of the quota.

2. When a bulldozer pushes earth or rock muck, or a scraper-loader hauls a loaded vehicle up a slope, and the gradient is greater than 5 percent, the haul distance is taken as the slant length of the sloping section multiplied by the corresponding factor of Table 1.

Table 1 Gradient factors. Gradient 5 to 10 percent, factor 1.75; gradient within 15 percent, factor 2.00; gradient within 20 percent, factor 2.25; gradient within 25 percent, factor 2.50.

3. The quantity of mechanized earth excavation is calculated as 90 percent excavated by machine and 10 percent excavated by hand; for the manually excavated portion the labour of the corresponding quota item is multiplied by a factor of 2.

4. The soil moisture content in the quota has been set on the basis of the natural moisture content. Where the moisture content reaches or exceeds 25 percent, the labour and machinery of the quota are multiplied by a factor of 1.15; where the moisture content exceeds 40 percent, the case is calculated separately.

5. Where the average thickness of the soil layer pushed by a bulldozer or scraped by a scraper-loader is less than 300 mm, the machine-shift quantity of the bulldozer is multiplied by a factor of 1.25.

6. Where an excavator operates on mattress boards, the labour and machinery are multiplied by a factor of 1.25; the quota does not include the material and machinery consumption needed for laying the mattress boards.

7. Where a bulldozer or a scraper-loader pushes or scrapes piled soil that has not been compacted, the quota item is multiplied by a factor of 0.73.

8. The earth for the ramps on which machinery travels up and down is combined into the quantity of earthwork and rockwork.

9. The haul roads for trucks have been determined comprehensively for road classes I, II and III, and account has been taken of the labour for cleaning the road during the haulage process; where paving materials are required, they are calculated separately.

1 Chapter 1 - Chapter Explanation, Rockwork

1. The blasting materials in this quota have been compiled for blastholes free of groundwater seepage and of standing water; where seepage or standing water appears in the blastholes, the cost of dealing with the seepage or the standing water is charged separately.

2. The rockwork quota items (general rock blasting, trench rock blasting, pit rock blasting) do not include the safety nets, straw bags, framed safety barriers and other facilities needed to cover the blast; where these occur, they are measured and charged as actually incurred.

3. The rock blasting quota has been compiled for loosening blasting by the blasthole method, without distinguishing between bench blasting and muffled blasting.

4. The rock blasting quota has been compiled for initiation by electric detonators and detonating cord. Where fuse blasting is adopted, the detonators are converted while the quantity remains unchanged; the gutta-percha lead wire is deducted from the quota and replaced by safety fuse, the length of the fuse being taken as 2.128 m for each detonator.

5. Controlled blasting means controlled rock blasting and excavation works where a group of buildings or important facilities lies within 300 m of the blasting area. Where a group of buildings or important facilities lies more than 300 m away from the blasting works area, protective measures must still be taken against the blast and this quota may be used for reference.

6. Controlled blasting is divided into three categories: bench (platform) controlled rock blasting, trench controlled rock blasting and pit controlled rock blasting. Bench controlled rock blasting applies to rock excavation above ground level; rock blasting below ground level is counted either as trench rock blasting or as pit rock blasting. A trench whose bottom width is 4 m or less and whose bottom length is less than three times the bottom width is counted as trench controlled rock blasting; where the trench width is greater than 4 m, the work is counted as pit controlled rock blasting. Where the trench excavation depth exceeds 4 m, 8 m or 12 m, the labour, materials and machinery of the quota are multiplied by 1.05, 1.10 and 1.3 respectively.

7. Covering and protection for controlled blasting in this quota: for a trench of bottom width 1.0 m or less under trench controlled rock blasting, one woven bag of ballast is provided for each blasthole and one bamboo mat cover for each four blastholes. For all other items, two woven bags are provided for each blasthole (one above and one below) and one bamboo mat cover for each two blastholes. Where canvas is used in place of the bamboo mats, the material cost is charged as actually incurred.

8. The distance from the blasting area means the distance from the outermost edge of the rock excavation area to the building, structure or facility to be protected. The quota has been compiled with the blasthole grid parameters and covering materials for a distance of 100 m to 200 m. Where the distance is greater than 200 m and less than 300 m, a factor of 0.85 is applied; less than 100 m and greater than 50 m, a factor of 1.15; less than 50 m and greater than 30 m, a factor of 1.3; less than 30 m and greater than 15 m, a factor of 1.5; less than 10 m, a factor of 2.

9. For small controlled rock blasting works with a quantity of less than 1000 cubic metres, the quota is multiplied by a factor of 1.10.

10. Where the design requires it, or where the following situations arise during construction, the cost is entered as direct cost:

10.1) Where the design requires, or where the side slope or the trench bottom has to be excavated at a specific batter angle, to a specific out-of-flatness or with a protective excavation, the cost is charged separately; the thickness of the protective layer to be charged separately shall not exceed 1 m.

10.2) Local support of the surrounding rock in special circumstances, safety strengthening of the surrounding houses and facilities, provision of safety barriers, blast vibration testing and the like are charged separately as actually incurred.

1 Chapter 1 - Table 2 Classification of Soils and Rocks (Protodyakonov Scale)

Table 2 classifies soils and rocks under the headings: quota classification, Protodyakonov class, name of soil or rock, average unit weight at natural moisture in kilograms per cubic metre, ultimate compressive strength in kilograms per square centimetre, drilling time per metre with a light drilling machine in minutes, excavation method and tools, and firmness coefficient f.

Class I (Class I-II soil): sand 1500; sandy soil 1600; humus soil 1200; peat 600. Excavated with a pointed shovel; firmness coefficient f 0.5 to 0.6.

Class II (Class I-II soil): light loam and loess-type soils 1600; damp and loose loess, soft saline and alkaline soils 1600; loose and soft gravel of average size within 15 mm 1700; dense humus soil containing grass roots 1400; peat and humus soil containing roots of diameter within 30 mm 1100; sand and humus soil mixed with pebbles, crushed stone and stone chips 1650. Excavated with a shovel with occasional use of a pick; firmness coefficient f 0.6 to 0.8.

Class III soil: fill soil cemented into lumps and containing pebble or crushed-stone impurities 1750; sandy loam containing pebbles, crushed stone and building rubbish 1900; heavy clay including the clay and clay-marl of the Carboniferous and Jurassic 1800; heavy loam and coarse gravel with crushed stone and pebbles of grain size 15 to 40 mm 1750; dry loess and loess of natural moisture content mixed with crushed stone or pebbles 1790; humus soil or peat containing roots of diameter greater than 30 mm 1400; soil mixed with crushed stone, pebbles or construction debris 1900. Excavated with a pointed shovel and at the same time a pick (30 percent); firmness coefficient f 0.81 to 1.0.

Class IV soil: clay with crushed stone, including the hard clays of the Jurassic and the Carboniferous 1950; rich clay and heavy loam containing crushed stone, pebbles, building rubbish and boulders up to 25 kg (within 10 percent of the total volume) 1950; boulder clay containing blocks of up to 50 kg amounting to 10 percent of the total volume 2000; mudstone (shale) 2000; material free of boulders or containing boulders of up to 10 kg 1950. Excavated with a pointed shovel and at the same time a pick and a crowbar (30 percent); firmness coefficient f 1.0 to 1.5.

Soft rock, Class V: moraine containing stones of up to 50 kg amounting to more than 10 percent of the volume 2100; diatomite and soft chalk 1800; weakly cemented conglomerate 1900; various non-solid schists 2600; gypsum 2200. Ultimate compressive strength less than 200 kilograms per square centimetre; drilling time less than 3.5 minutes per metre; excavated partly with hand tools and partly by blasting; firmness coefficient f 1.5 to 2.0.

Medium-hard rock, Class VI: tuff and pumice 1100; porous and badly fissured soft limestone and shelly limestone 1200; schist of medium hardness 2700; limestone of medium hardness 2300. Strength 200 to 400 kilograms per square centimetre; drilling time 3.5 minutes per metre; excavated by the pneumatic-pick blasting method; firmness coefficient f 2.0 to 4.0.

Medium-hard rock, Class VII: conglomerate containing pebbles and sedimentary rock cemented with limestone 2200; weathered and widely fissured clayey soft rock 2000; solid mudstone (shale) 2800; solid marly limestone 2500. Strength 400 to 600 kilograms per square centimetre; drilling time 6.0 minutes per metre; excavated by the blasting method; firmness coefficient f 4.0 to 6.0.

Medium-hard rock, Class VIII: gravelly granite 2300; marly limestone 2300; clayey sandstone 2200; sandy gneiss 2300; anhydrite 2900. Strength 600 to 800 kilograms per square centimetre; drilling time 8.5 minutes per metre; excavated by the blasting method; firmness coefficient f 6.0 to 8.0.

Ordinary hard rock, Class IX: heavily weathered weak granite, gneiss and syenite 2500; talcose serpentine 2400; dense limestone 2500; conglomerate cemented with siliceous material and containing pebbles and sedimentary rock 2500; sandstone 2500; sandy limestone schist 2500; magnesite 3000. Strength 800 to 1000 kilograms per square centimetre; drilling time 11.5 minutes per metre; excavated by the blasting method; firmness coefficient f 8.0 to 10.0.

Ordinary hard rock, Class X: dolomite 2700; solid limestone 2700; marble 2700; dense conglomerate cemented with limestone 2600; solid sandy schist 2600. Strength 1000 to 1200 kilograms per square centimetre; drilling time 15.0 minutes per metre; excavated by the blasting method; firmness coefficient f 10 to 12.

Extra-hard rock, Class XI: coarse granite 2800; extremely hard dolomite 2900; serpentine 2600; conglomerate containing igneous-rock pebbles cemented with limestone 2800; solid sandstone cemented with quartz 2700; coarse-grained syenite 2700. Strength 1200 to 1400 kilograms per square centimetre; drilling time 18.5 minutes per metre; excavated by the blasting method; firmness coefficient f 12 to 14.

Extra-hard rock, Class XII: andesite and basalt bearing traces of weathering 2700; gneiss 2600; extremely solid Carboniferous rock 2900; conglomerate containing igneous-rock pebbles cemented with siliceous material 2900; coarse trachyte 2600. Strength 1400 to 1600 kilograms per square centimetre; drilling time 22 minutes per metre; excavated by the blasting method; firmness coefficient f 14 to 16.

Extra-hard rock, Class XIII: medium-grained granite 3100; solid gneiss 2800; diabase 2700; porphyrite 2500; solid trachyte 2800; medium-grained syenite 2800. Strength 1600 to 1800 kilograms per square centimetre; drilling time 27.5 minutes per metre; excavated by the blasting method; firmness coefficient f 16 to 18.

Extra-hard rock, Class XIV: extremely solid fine-grained granite 3300; granite gneiss 2900; diorite 2900; limestone of high hardness 3100; solid porphyrite 2700. Strength 1800 to 2000 kilograms per square centimetre; drilling time 32.5 minutes per metre; excavated by the blasting method; firmness coefficient f 18 to 20.

Extra-hard rock, Class XV: andesite, basalt and solid hornstone 3100; diabase and diorite of high hardness 2900; solid gabbro and quartzite 2800. Strength 2000 to 2500 kilograms per square centimetre; drilling time 46 minutes per metre; excavated by the blasting method; firmness coefficient f 20 to 25.

Extra-hard rock, Class XVI: labradorite basalt and olivine basalt 3300; especially solid grey gabbro-diabase, quartzite and porphyrite 3000. Strength greater than 2500 kilograms per square centimetre; drilling time greater than 60 minutes per metre; excavated by the blasting method; firmness coefficient f greater than 25.

2 Chapter 1 - Rules for the Calculation of Quantities

1. Except for loose fill, the volumes of earthwork and rockwork are all calculated as natural dense solid volume. Where conversion from natural dense solid volume becomes necessary, the numerical conversion may be made in accordance with Table 3.

Table 3 Volume conversion. Loose volume 1.00 corresponds to natural dense solid volume 0.77, tamped volume 0.67 and loose fill volume 0.83; loose volume 1.30 corresponds to natural dense solid volume 1.00, tamped volume 0.87 and loose fill volume 1.08; loose volume 1.50 corresponds to natural dense solid volume 1.15, tamped volume 1.00 and loose fill volume 1.25; loose volume 1.20 corresponds to natural dense solid volume 0.92, tamped volume 0.80 and loose fill volume 1.00.

2. Manual site levelling means levelling in situ where the average difference between the original ground and the design outdoor finished level (whether higher or lower) is within 30 cm.

3. The quantity of site levelling is calculated from the bottom area of the building or structure, with 2 m added on each side beyond the outer line.

4. Division between trenches and pits: any excavation shown on the drawing with a bottom width within 3 m and with a trench length greater than three times the trench width is a trench. Any excavation whose bottom area shown on the drawing is within 20 square metres is a pit. Where the trench bottom width shown on the drawing exceeds 3 m, where the pit bottom area exceeds 20 square metres, or where the levelling excavation thickness exceeds 30 cm, the work is calculated as earth excavation.

5. Where the full depth of a trench or a pit exceeds the depth given in Table 4, the battering (side-slope) quantity shall be calculated.

Table 4 Side-slope coefficients. Class I-II soil: slope starting point 1.20 m; manual excavation 1 to 0.50; mechanical excavation working inside the pit 1 to 0.33; mechanical excavation working above the pit 1 to 0.75. Class III soil: slope starting point 1.50 m; manual excavation 1 to 0.33; working inside the pit 1 to 0.25; working above the pit 1 to 0.67. Class IV soil: slope starting point 2.00 m; manual excavation 1 to 0.25; working inside the pit 1 to 0.10; working above the pit 1 to 0.33.

Note 1 to Table 4: where the soil classes within a trench or a pit differ, the slope starting point and the slope coefficient are taken separately for each class and calculated as a weighted average according to the thickness of the different soils.

Note 2 to Table 4: when the battering is calculated, the repeated quantity at intersections is not deducted; where the original trench or pit is used as the foundation bedding, the batter is calculated from the top surface of the bedding.

6. Where retaining boards have to be provided for the excavation of a trench or a pit, the width is calculated as the trench or pit bottom width shown on the drawing plus 10 cm for one side or 20 cm for both sides. The area of the retaining boards is calculated as the vertical projected area of the trench or pit; once retaining boards have been provided, no battering may be calculated in addition.

7. The working face for foundation construction is calculated in accordance with Table 5.

Table 5 Width of working face required for foundation construction, added on each side, in millimetres: brick foundation 200; mortar-laid rubble and ashlar foundation 150; formwork for the concrete foundation bedding 300; formwork for the concrete foundation 300; waterproofing layer on the vertical face of the foundation 800 (measured to the waterproofed face).

8. The length of trench excavation is calculated on the centre line shown on the drawing for external walls and on the net length between the foundation bottom faces shown on the drawing for internal walls; the volume of internal and external projections (pilasters, wall-attached flues and the like) is combined into the trench earthwork quantity.

9. Where the depth of manual earth excavation exceeds 1.5 m, work-days are added in accordance with Table 6.

Table 6 Work-days added for excess depth in manual earth excavation, unit 100 cubic metres: depth within 2 m, 5.55 work-days; depth within 4 m, 17.60 work-days; depth within 6 m, 26.16 work-days.

10. Pipe trench excavation is calculated on the centre-line length shown on the drawing. The trench bottom width is calculated at the dimension laid down by the design where the design lays one down; where the design lays down no dimension, the widths given in Table 7 may be used.

Table 7 Calculation of pipe trench bottom width, in metres, for cast iron pipe, steel pipe and asbestos cement pipe and for concrete, reinforced concrete and prestressed concrete pipe respectively, by pipe diameter in millimetres: 50 to 70, 0.60 and 0.80; 100 to 200, 0.70 and 0.90; 250 to 350, 0.80 and 1.00; 400 to 450, 1.00 and 1.30; 500 to 600, 1.30 and 1.50; 700 to 800, 1.60 and 1.80; 900 to 1000, 1.80 and 2.00; 1100 to 1200, 2.00 and 2.30; 1300 to 1400, 2.20 and 2.60.

Note 1 to Table 7: when the pipe trench earthwork quantity is calculated from the above table, the additional earth volume required for widening at the various manholes and at the pipe joints (cast-iron water-supply pipes excepted) is not calculated separately; for manholes with a bottom area larger than 20 square metres, the additional quantity is combined into the pipe trench earthwork.

Note 2 to Table 7: when cast-iron water-supply pipelines are laid, the additional earth volume at their joints and similar points may be calculated as 2.5 percent of the total trench earthwork of the cast-iron water-supply and drainage pipelines.

11. The depth of trenches and pits is calculated from the level shown on the drawing at the trench bottom or pit bottom up to the outdoor finished level; the depth of a pipe trench is calculated from the trench bottom shown on the drawing up to the outdoor finished level.

12. The earthwork quantity for manually dug pile holes is calculated as the pile cross-sectional area shown on the drawing multiplied by the design depth at the centre line of the pile hole.

13. For the backfilling of trenches and pits, the backfill volume is calculated as the excavated volume less the volume of the structures buried below the design outdoor finished level (including the foundation bedding, the foundations and the like).

14. For the backfilling of pipe trenches, the volume is calculated as the excavated volume less the volume occupied by the pipe. For pipes of diameter 500 mm and below the volume occupied by the pipe is not deducted; where the pipe diameter exceeds 500 mm, the volume occupied by the pipe is deducted in accordance with Table 8.

Table 8 Earth volume deducted for pipelines, in cubic metres per metre, by pipe diameter in millimetres. Steel pipe: 501 to 600, 0.21; 601 to 800, 0.44; 801 to 1000, 0.71. Cast iron pipe: 501 to 600, 0.24; 601 to 800, 0.49; 801 to 1000, 0.77. Concrete pipe: 501 to 600, 0.33; 601 to 800, 0.60; 801 to 1000, 0.92; 1101 to 1200, 1.15; 1201 to 1400, 1.35; 1401 to 1600, 1.55.

15. Backfill within the building (room-core backfill) is calculated as the area between the main walls multiplied by the backfill thickness.

16. The quantity of surplus earth to be hauled off site, or of earth to be borrowed, may be calculated by the following formula: volume of surplus earth hauled off site equals total excavated earth volume minus total backfill earth volume. Where the result of the calculation is positive it is the volume of surplus earth to be hauled off site; where it is negative it is the volume of earth that has to be borrowed.

17. The bulldozer haul distance is calculated as the straight-line distance between the centre of gravity of the excavation area and the centre of gravity of the backfill area.

18. Manual rock chiselling is calculated in cubic metres from the dimensions shown on the drawing.

19. Rock blasting is calculated in cubic metres from the dimensions shown on the drawing. For the depth of foundation trenches and pits the permitted over-excavation is 200 mm for medium-hard rock and 150 mm for extra-hard rock, and the over-excavated rock is combined into the rock excavation quantity.

20. Pre-split blasting is calculated in square metres of pre-split face; the calculation method is the accumulated drilling depth of the down-the-hole drill multiplied by the drillhole spacing.