PO162

Standardisation of Offshore Wind Substations: Fire- and blast resistant sandwich panels.

Berend Groeneveld
InterDam, Ridderkerk, The Netherlands

Abstract

This paper provides an update on the usability of fire and blast resistant sandwich panels for onshore and offshore installations. This paper trails the paper: ‘Four generations of fire and blast resistant walls’ published in the FABIG newsletter issue 68 (February 2016).

In this paper a new generation, generation V is introduced.

Sandwich panels can be regarded as the fifth generation of fire and blast resistant walls, which provides both weight and cost savings as compared to earlier generations. With the introduction of this generation V sandwich panel a main dissatisfier to not use sandwich panels in blast resistant walls is addressed.

Method

Steel blast wall H120 comparison table – CAPEX (capital expenditure) comparison table (relative %)(mild steel, 4 metres span including horizontal support  if required)

Overpressure:

0.3 bar(200 ms)

Wall Type:

Generation I

Stressed skin

Generation II

Corrugated skin

Generation III

Built-up wall

Generation IV

Prefabricated sandwich construction

Generation V

Blast rated sandwich wall

Steel + insulation + int. skin

100

98

65

-

50

Installation (incl. welding)

100

100

50

-

30

Coating

100

100

40

-

20

Total CAPEX

100

96

60

-

40

 

 

Results

 

Steel blast wall, H120 comparison table – Weight (kg/m2)

(mild steel, 4 metres span including horizontal support if required)

Overpressure:

(200 ms)

Wall Type:

Generation II

Corrugated skin

Generation III

Built-up wall

Generation IV

Prefabricated sandwich construction

Generation V

Blast rated sandwich wall

0,15 bar

90

65

45

35

0,30 bar

95

75

-

40

0,45 bar

100

85

-

45

0,60 bar

105

85

-

52

0,80 bar

115

85

-

55

1,00 bar

130

115

-

67

Table 2 Weight comparison table of the 5 generations of steel blast walls

Conclusions

A recently carried out series of tests has demonstrated that optimized sandwich panels can withstand blast overpressure in excess of 1,0 bar whilst retaining their fire and air-tightness properties. This design evolution allows engineers to standardise the design of non-loadbearing blast and fire resistant walls.

The series of tests and consecutive development of dynamic prediction models provide the following conclusions that are substantiated in the paper:

-        Sandwich panels combined with an adapted rail- and fixing system can substitute “conventional” walls for substantial higher blast pressures than assumed before.

 

-        The dynamic prediction models now allow for efficient and reliable project specific solutions for safe blast response by the Generation V sandwich wall system.

Objectives

New possibilities for lightweight and cost-saving blast wall system for Offshore wind projects. Tuesday 20 December 2016 we will give an webinar about this subject. After the webinar we have more information to make the test results, from the blast panel test of November 2016, more clear.