SS Grade 33
Specification details for SS Grade 33

EN_US-Engineering-Product-Hot-Rolled-Durbar floor plate-All grades Overview

Overview

There is patterned steel floor plate - and there is Durbar® - Only by Tata Steel


Outstanding slip resistance

Slips and trips are the most common cause of injuries at work. Durbar’s unique pattern of raised studs has been proven, by external laboratory testing, to provide outstanding resistance to slip, in both dry and wet conditions.


Fire resistance

Durbar's structural properties mean that you can rely on it to perform, even when subjected to extreme heat. At temperatures where aluminium floor plates have begun to melt, Durbar steel floor plate will still be supporting design loads.


Saving you money

Durbar's structural properties reduce cost by eliminating the need for separate structural and flooring components – a distinct advantage over other materials, such as aluminium.


Easy to clean, self-draining surface

Durbar's evenly distributed, raised stud pattern creates a self-draining surface which is easy to clean. The process of producing Durbar even produces an abrasion-resistant surface, giving it a long service life.


Load span data

Members of The Steel Construction Institute can view load span data for Durbar at www.steelbiz.org, in table C242, floor plates simply supported, from the Steel Designers Manual, 6th Edition, 2003.

Applications

  • Bridges
  • Cladding and protective barriers
  • Commercial vehicles
  • Containers
  • Lifts
  • Offshore installations
  • Shipbuilding
  • Stairs and walkways
  • Steps and safety platforms

Relationship with standards

Durbar meets the mechanical and chemical properties of ASTM A1011 and A1018 structural grades.
Durbar meets the floor plate specification ASTM A786. 

 

EN_US-Engineering-Product-Hot-rolled-All Grades Surface aspects Supply Conditions

Supply conditions

Hot-rolled steel can be supplied with these product conditions and finishes and with this surface treatment:

Side/surface condition non-pickled pickled pickled and oiled
Mill edges Yes Yes Yes
Trimmed edges - Yes Yes
 
Trimmed edges available in thicknesses up to 0.25inch.
The steel grades shown on the following pages belong to the standard range offered by Tata Steel.
Please contact us regarding other specifications we may have that meet your needs. You can find details on how to get in touch with us in 'Contact Us' below.
 

Surface aspects

Description Availability
Surface finish Coils are available in non-pickled and pickled finish for most grades.  For grade specific availability, please refer to the dimensional tables.
Oiling Pickled finish is available with rolling
or preservative oil applied. 
Oil weight normally 55 - 275 mg/ft2

Alternative oiling ranges are available.
Please contact us for details. You can find details on how to get in touch with us in 'Contact Us' below.

 

EN_US-Engineering-Product-Hot-Rolled-Durbar floor plate-SS Grade 33-Properties

Properties

Properties

Mechanical properties

The mechanical properties of Durbar comply with ASTM A1011 or ASTM A1018 and are shown in the table below.
The values shown for strength and elongation are for test pieces taken transverse to the rolling direction; those for the impact test are for test pieces taken in the rolling direction. 

ASTM A1011-15
ASTM A1018-16
Grade SS Grade 33
Min. yield strength ksi 33
Tensile strength ksi 52
Elongation (%)1  t < 0.064 18
0.064 ≤ t < 0.097 22
0.097 ≤ t < 0.23 23
0.23 ≤ t 22
t - material thickness in mm.
1. Min. elongation after fracture A (%). L0 = 2 inch

Chemical composition

The chemical composition of Durbar complies with ASTM A1011 and A1018 and is shown in the table below. 

  Grade SS Grade 33
C Max. 0.25
Mn Max. 0.9
P Max. 0.035
S Max. 0.04
Si Max. -
N Max. -

 

EN_US-Engineering-Product-Hot-Rolled-Durbar floor plate-SS Grade 33-Dimensions

Dimensions

Dimensions

Dimensional capability (non-pickled)

Dimensions in inches.

Ympress / HSLAS grade
Thickness Max. width
From - up to Ympress 40
0.060 - 0.070 51
0.070 - 0.080 60
0.080 - 0.090 68
0.090 - 0.100 73
0.100 - 0.110 78
0.110 - 0.120 80
0.120 - 0.130 81
0.130 - 0.140 81
0.140 - 0.150 81
0.150 - 0.160 81
0.160 - 0.170 81
0.170 - 0.180 81
0.180 - 0.190 81
0.190 - 0.200 81
0.200 - 0.210 81
0.210 - 0.220 81
0.220 - 0.230 81
The minimum width is 35 inch.

Dimensional capability (pickled)

Dimensions in inches.

Ympress / HSLAS grade
Thickness Max. width
From - up to Ympress 40
0.060 - 0.070 51
0.070 - 0.080 60
0.080 - 0.090 68
0.090 - 0.100 73
0.100 - 0.110 78
0.110 - 0.120 80
0.120 - 0.130 79
0.130 - 0.140 78
0.140 - 0.150 78
0.150 - 0.160 78
0.160 - 0.170 78
0.170 - 0.180 78
0.180 - 0.190 78
0.190 - 0.200 74
0.200 - 0.210 70
0.210 - 0.220 66
0.220 - 0.230 62
The minimum width is 35 inch.

Tolerances on thickness

Tolerances for wide strip and slit wide strip comply with standard ASTM A568: 2007 and A635: 2007.
Tighter tolerances are available, please contact us. Tolerances are over, no under.

 

EN_US-Engineering-Product-Hot-rolled-All grades Shape and dimensional tolerances

Shape and dimensional tolerances

Shape and dimensional tolerances

Tolerances on thickness

Tata Steel can supply to full thickness tolerance specified in ASTM A568: 2015 / A635: 2015.
Thickness tolerances over, no tolerance under.
Tighter tolerances are available as shown below:

Carbon Steel Thickness tolerances available
ASTM A 568 (2015) / A635 (2015)
20 - 40 40 - 48 48 - 60 60 - 72 >72
0.031 - 0.051 0.01 0.01 0.01 0.01 0.01
0.051 - 0.057 0.01 0.012 0.012 0.014 0.014
0.057 - 0.071 0.012 0.012 0.014 0.014 0.014
0.071 - 0.098 0.014 0.014 0.014 0.016 0.016
0.098 - 0.179 0.014 0.016 0.016 0.016 0.016
0.179 - 0.229 0.016 0.018 0.02 0.022 0.024
0.229 - 0.313 0.022 0.024 0.024 0.026 0.03
0.313 - 0.375 0.024 0.026 0.028 0.03 0.032
0.375 - 0.500 0.028 0.028 0.03 0.032 0.036
0.500 - 0.625 0.03 0.03 0.032 0.036 0.038
0.625 - 1.000 0.032 0.032 0.034 0.038 0.04

 

 

HSLA Thickness tolerances available
ASTM A568 (2015) / A635 (2007)
20 - 32 32 - 40 40 - 48 48 - 60 60 - 72 72 - 80 > 80
0.031 - 0.051 0.012 0.012 0.012 0.012 0.012 0.012 0.012
0.051 - 0.059 0.012 0.012 0.014 0.014 0.014 0.014 0.014
0.059 - 0.070 0.014 0.014 0.014 0.014 0.016 0.016 0.016
0.070 - 0.082 0.014 0.014 0.014 0.014 0.016 0.016 0.016
0.082 - 0.098 0.014 0.016 0.116 0.016 0.018 0.018 0.02
0.098 - 0.179 0.016 0.016 0.02 0.02 0.022 0.024 0.024
0.179 - 0.229 0.018 0.018 0.02 0.02 0.022 0.024 0.024
0.229 - 0.313 0.022 0.022 0.024 0.024 0.026 0.03 0.03
0.313 - 0.375 0.024 0.024 0.026 0.028 0.03 0.032 0.032
0.375 - 0.500 0.028 0.028 0.028 0.03 0.032 0.036 0.036
0.500 - 0.625 0.03 0.03 0.03 0.032 0.036 0.038 0.038
0.625 - 1.000 0.032 0.032 0.032 0.034 0.038 0.04 0.04

 

Option for maximum crown values

At the time of ordering, specific agreements can be made on the crown of hot-rolled strip.

 

Tolerances on width, edge camber and flatness

Material will be supplied conforming to the tolerances specified in ASTM A568 (2007) / A635 (2007). Width tolerances are over, no tolerance under.

Width tolerances available  
Carbon steel ASTM A568: 2015 / A635: 2015
Mill edge Cut edge
24 - 26 0.812 0.125
26 - 28 0.937 0.125
28 - 30 0.937 0.125
30 - 35 1.125 0.187
35 - 48 1.125 0.187
48 - 50 1.125 0.25
50 - 60 1.5 0.25
60 - 65 1.5 0.312
65 - 70 1.5 0.312
70 - 78 1.5 0.312
78 - 80 1.875 0.312
80 - 82 1.875 0.375

 

Width tolerances available  
HSLA ASTM A568: 2015 / A635: 2007
Mill edge Cut edge
24 - 26 0.812 0.125
26 - 28 0.937 0.125
28 - 30 1.125 0.125
30 - 35 1.125 0.187
35 - 48 1.25 0.187
48 - 50 1.25 0.25
50 - 60 1.5 0.25
60 - 65 1.625 0.312
65 - 70 1.75 0.312
70 - 78 1.875 0.312
78 - 80 2 0.375
80 - 82 1.875 0.375

 

 

Dimensions and coil weights

Tata Steel can supply hot-rolled steels with the following minimum and maximum dimensions and weights.

Description Capability
Coil diameter inner non-pickled 30 inch
Coil diameter inner pickled 24 inch standard
30 inch on request
Tolerance on inner diameter +0/-2 inch
Coil diameter outer non-pickled Outer diameter available is 10/7 x width to reduce possibility of coil tipping over
Max. 86 inch
Min. 41.5 inch
Coil diameter outer pickled and oiled Outer diameter available is 10/7 x width to reduce possibility of coil tipping over
Max. 86 inch
Min. 65 inch
Coil weight Max. 75,000 lbs
Maximum coil weight limits can vary due to
transport limits and outer coil diameter
Some HR products may have different coil weight ranges
PIW  width ≤ 47 inch 868 - 1288 PIW width
PIW  47 inch < width ≤ 67 inch 868 - 1215 PIW width
PIW  width > 67 inch 616 PIW width and 868 - 1215 PIW width
Minimum tonnage per order Refer to price list for order quantity details
Minimum order quantities may apply

 

 

 

EN-Engineering-Product-Hot-Rolled-Durbar floor plate-All grades-Design

Design

Using Durbar®

Durbar is a non-slip raised pattern floor plate of integral manufacture (the pattern is rolled in not welded). The "tear drop" studs are distributed to give maximum slip resistance in a variety of applications whilst ensuring a free draining surface.

The nominal gauge of Durbar is the thickness of the plain plate exclusive of pattern.

Unit Area Density

Thickness on plain Mass
(mm) (kg/m2)
3 26.83
4.5 38.59
6 50.36
8 66.04
10 81.73

12.5

101.34

Capacity Tables

It is usual to consider floor plates as supported on all four edges although stiffeners or joint covers may only support two edges. If the plates are securely bolted or welded to the supporting system, they may be considered as encastré. This increases the load carrying capacity slightly but reduces the deflection considerably.

The thickness given is exclusive of any raised pattern i.e. on plain.
The breadth is the smaller dimension and the length the greater, irrespective of the position of the main support members.
The maximum uniformly distributed load on the plate (w) is given by Pounder's formula and the maximum skin stress is limited to the design strength py

For calculating the maximum deflection (dmax) at serviceability, the uniformly distributed imposed load (wimp) on the plate is derived as follows.

w = gdead wdead + gimp wimp
wimp = (w - gdead wdead)/ gimp

For plates simply supported on all four edges

This formula assumes that there is no resistance to uplift at plate corners.

w = a1 py t2 / k B2 [ 1 + a2(1-k) + a3(1-k)2]
dmax = a4 k wimp B4 [1+a5(1-k) + a6(1-k)2] / E t3

Where resistance to uplift at corners is provided, the above formula will be conservative. Higher values may be obtained by assuming encastré status as outlined below.

For plates encastré on all four edges

The plate must be secured to prevent uplift, which would otherwise occur at the plate corners.

w = a7 py t2 / k B2 [ 1 + a8(1-k) + a9(1-k)2]
dmax = a10 k wimp B4 [1+a11(1-k) + a12(1-k)2] / E t3

Where:

L = length of plate (mm) (L > B)
B = breadth of plate (mm)
t = thickness of the plate on plain (mm)
k = L4/(L4+ B4)
py = design strength of plate ( 275 N/mm2 or 355 N/mm2)
E = Young's modulus (205 x 103 N/mm2)
1/m = Poisson's ratio (m = 3.0)
gdead = load factor for dead load (1.4)
gimp = load factor for imposed load (1.6)
dmax = maximum deflection (mm) at serviceability due to imposed loads only
w = uniformly distributed load on plate (ultimate) (N/mm2)
wdead = uniformly distributed self weight of plate (N/mm2)
wimp = uniformly distributed imposed load on plate (N/mm2)
a1 to a12 are constants as below:

Constant Value
a1 = 4/3
a2 = 14/75
a3 = 20/57
a4 = (5m2 -5)/32m2
a5 = 37/175
a6 = 79/201
a7 = 2
a8 = 11/35
a9 = 79/141
a10 = (m2 -1)/32m2
a11 = 47/210
a12

= 200/517

 

Durbar ultimate load capacity –various sized plates

Fixed on all four sides (encastré)

The ultimate uniformly distributed load for various sizes of Durbar plates fixed on all four sides and stressed to 275N/mm2 can be determined by using the table. The values are based upon equations developed by C.C. Pounder and conform to the construction and fixing requirements in BS 4592-5 : 2006.  The values in the tables are theoretical; in-use performance may vary. This information should not be used without the advice of a qualified structural engineer. Users of this information should satisfy themselves that it is suitable for their purpose.

Ultimate load capacity (kN/m2) for Durbar fixed on all four sides and stressed to 275N/mm2 

Values obtained with plates secured to prevent uplift

Thickness (t)   Ultimate distributed load (kN/m2) for length, L, (mm)
(mm) Breadth, B, (mm) 600 800 1000 1200 1400  1600  1800  2000 
3 600  21.2  16.3  14.9  14.3  14.1  13.9  13.9  13.8
  800    10.7§  8.4§  7.5§  7.1§  6.9§  6.8§  6.7§
  1000      5.6§  4.6§  4.2§  3.9§  3.8§  3.7§
  1200        3.4§  2.9§  2.6§  2.5§  2.4§
  1400          2.3§  2.0§  1.8§  1.7§
4.5 600  47.7 36.8 33.5  32.2  31.6  31.4  31.2  31.1 
  800    26.8 21.5  19.5  18.6  18.1  17.9  17.7 
  1000      17.2 14.2  12.9  12.2  11.8  11.6 
  1200        10.8 § 9.1 § 8.2 § 7.7 § 7.4 §
  1400          7.0 § 6.0 § 5.5 § 5.1 §
6 600  84.8 65.4  59.5  57.3  56.2  55.7  55.5  55.3 
  800    47.7 38.3  34.7  33.1  32.2  31.7  31.5 
  1000      30.5 25.3  22.9  21.7  21.0  20.6 
  1200        21.2 18 16.3  15.4  14.9 
  1400          15.6 13.4  12.3  11.6
8 600  150.8 116.2 105.9 101.8 100 99.1 98.6 98.3 
  800    84.8 68.1  61.7  58.8  57.3  56.4  56.0 
  1000      54.3 44.9  40.7  38.6  37.4  36.7 
  1200        37.7 31.9  29.0  27.4  26.5 
  1400          27.7 23.9  21.8  20.6 
10 600  235.5 181.5  165.4  159.1  156.2  154.8  154.1  153.6 
  800    132.5 106.4  96.4  91.8  89.5  88.2  87.4 
  1000      84.8 70.2  63.7  60.3  58.4  57.3 
  1200        58.9 49.9  45.4  42.9  41.3 
  1400         43.3 37.3  34.1  32.2 
12.5 600  368.0 283.6  258.4  248.6  244.1  241.9  240.7  240.0 
  800    207.0 166.2  150.7  143.5  139.8  137.8  136.6 
  1000      132.5 109.7  99.5  94.2  91.2  89.5 
  1200        92.0 77.9  70.9  67.0  64.6 
  1400          67.6 58.3  53.3  50.3 
†. Stiffeners should be considered for spans in excess of 1100mm to avoid excessive deflections.
§. Loads have been limited so that deflection ≤B/100 at serviceability, where serviceability is due to the imposed load only

Fire safety

Reaction to fire

Durbar hot-rolled steel floor plate is non-combustible and has a fire rating of A1 (and A1FL for flooring). This applies to both the UK and Europe. It qualifies as a Classification Without Further Testing (CWFT) material mentioned in Approved Document B (Fire safety) Volumes 1 and 2, and set out in EC Decision 96/603/EC. These materials have known behaviour during a fire, and therefore do not need to undergo additional testing. 

A1 and A1FL are the highest ratings achievable; materials with these ratings are non-combustible and will not contribute to a fire through their own degradation, nor will they generate smoke or burning droplets during a fire.

Resistance to fire

Fire resistance ratings are determined via testing, according to various standards (including but not limited to BS EN 13501-2, BS 476-21, BS 476-22 for the UK and EU). The regulations may require a specific application to be submitted for fire resistance testing. It is the responsibility of the customer to ensure that any form of construction which includes Durbar floor plate meets the required fire resistance rating.

Fire resistance ratings are required within buildings in many, but not all, situations; this includes load bearing elements of construction such as floors. These requirements vary for different scenarios and building purpose groups. Fire resistance ratings are not always required under certain circumstances, for example; platform floors, external horizontal and external vertical means of escape, and raised storage areas in single-storey buildings used for storage and industrial purposes.

The customer must satisfy themselves that they comply with the relevant national requirements for fire resistance ratings. These and any exclusions are detailed in Approved Document B (Fire safety) Volumes 1 and 2 for the UK.

 

 

EN-Engineering-Product-Hot-Rolled-Durbar floor plate-All grades-Proven slip-resistance

Proven slip-resistance

Unique self-draining stud pattern provides a slip-resistant surface
 

Keeping you safe

According to the UK Health and Safety Executive (HSE), over a third of all major injuries reported in the UK each year are caused as a result of a slip or trip1. That amounts to 172,000 injuries to workers every year, not counting injuries to the general public.

Products that contribute to safer passage over surfaces, can reduce the risk of slips and trips, whether in permanent conditions, such as in factories, or temporary conditions, such as construction, building and planned maintenance.

The dense pattern of studs on Durbar creates a slip-resistant surface at all angles and allows plates to be used in any direction. Durbar has a unique diamond pattern which, on average, is 23% deeper and has 10% more studs than other generic steel floor plates.
 

Tested and trusted

In recent independent tests carried out on genuine Durbar floor plate, slip resistance was found to be consistently good, in both dry and wet conditions.

The UK HSE and the influential UK Slip Resistance Group (UKRSG) recommend the use of a pendulum test to measure the slip resistance of flooring products. This test is according to EN 13036-4. The pendulum test measures the dynamic coefficient of friction and is designed to replicate a pedestrian heel strike. This has been found to best simulate the most common cause of slips.

Independent tests on genuine Durbar using the pendulum tester according to EN 13036-4 have shown consistently goodresults in both wet and dry conditions2. The measured pendulum test value (PTV) in the wet condition of 46 represents a ‘Low’ slip potential, according to UKSRG guidelines, while in the dry condition, a PTV of 73 provides a classification of ‘Extremely low’ slip potential.

Comparative tests on generic floor plate adopting either ‘T’or ‘A’ patterns have shown that the unique pattern of studs on genuine Durbar results in the lowest all-round slip potential.

The actual slip resistance of Durbar or any other floor plate willdepend on real-life application and the environment in which it is used. Galvanising, painting or coating Durbar can influence the slip resistance.


 

Pendulum test comparison

The table below, taken from UKSRG guidance, represents the risk category for a reasonably active pedestrian between 18 and 60, walking in a straight line on a level surface.

Pendulum Value Potential for Slip
0-24 High
25-35 Moderate
36-64 Low
65+ Extremely Low
 
Item Potential for Slip  Potential for Slip
Durbar® from Tata Steel Extremely Low Low
Generic Type `T` floor plate Low Low
Generic Type `A` floor plate Low Low
1. UK Health & Safety Executive Statistics, 2017/18 ; non-fatal injuries to workers according to self-reported estimates from the Labour Force Surve
2. External laboratory results performed according to BS EN13036-4 BS7976 / UK Slip Resistance Group guidelines, Wessex Precision Instruments Ltd, July 2019

EN-Engineering-Product-Hot-Rolled-Durbar floor plate-All grades-FAQs

FAQs

Frequently Asked Questions (FAQs)

What is the fire resistance of Durbar?

Durbar hot rolled steel floor plate is classed as non-combustible. When subjected to extreme heat, Durbar has distinct advantages over some other flooring materials. At temperatures where aluminium alloys have already begun to melt, Durbar steel floor plate will still be supporting design loads. The fire performance of an assembly is specific to the construction of that assembly and so we strongly recommend you check your fire rating with a qualified fire engineer.

What is the slip resistance of Durbar?

Durbar has been tested to BS 7976-2:2002 for slip resistance and found to have Extremely Low slip potential in the dry state and Low slip potential even when wet. The unique Durbar pattern ensures this optimised slip resistance and in comparison tests, competitors’ floor plate products display a lower slip resistance.

Will galvanising and painting Durbar affect it’s characteristics?

Independent testing, in both wet and dry conditions in accordance with BS7976-2 assessed as-supplied Durbar as extremely low slip when dry, and low slip when wet. Moreover, Durbar is self-draining.

Galvanising and/or painting will alter the surface condition,  and thus the slip resistance – we suggest you  should consult the paint manufacturer for details of appropriate paint systems. 

Can Tata Steel provide calculations for my specific use case of Durbar?

Durbar is stronger than ordinary mild steels, easily fabricated, and therefore well suited to performing a structural role efficiently. We provide load capacity tables for typical configurations of Durbar in the Design section of this web-page, which cover a range of representative cases. For specific use cases, we recommend that you consult an independent design engineer.

Can I buy individual sheets of Durbar from Tata Steel?

We manufacture Durbar in coil form and can supply both coil and cut sheet. We are the largest distributor in the UK of Durbar in a cut-sheet format. We supply Durbar sheet to an extensive range of local stockists that can provide product in appropriate sizes and quantities for specific end use requirements and projects

Is Durbar a sustainable choice?

Durbar is a structurally efficient choice for slip-resistant, hard-wearing and long-lasting flooring. Compared to some alternatives, less supporting structure is required. Durbar itself is 100% truly recyclable steel – indeed every sheet of Durbar includes a significant proportion of recycled steel.

Durbar has been in use in structures for over 50 years and remains the benchmark in textured floorplate in the UK – the ability to match the pattern with existing material in use makes it excellent for prolonging the life of existing structures.