Clogging of Industrial High Efficiency Particulate Air (HEPA) Filters in Case of Fire: From Analytical to Large-Scale Experiments

Figures & data

FIG. 1. Experimental test bench BANCO for the combustion of fuels and clogging of HEPA filters.

FIG. 2. DIVA experimental test bench for the combustion of fuels and clogging of HEPA filters on a large scale (courtesy of IRSN/PSN-RES/SA2I/LEF).

Table 1 Properties of the studied fuels

Facility	Fuel	Nature	Composition	Illustration
Small scale, high air change rate “BANCO”	KIOWAGLASS	Polymer	70% – (C5H8O2)n
			30% – Pb
	LEXAN	Polymer	Polycarbonate (C15H16O2)n
	Electrical cable A	Cable	Non-halogen cable
	Electrical cable B	Cable	Halogen cable
	Electrical cable C	Cable	mostly PVC (C2H3Cl)n
	TBP / TPH (30/70)*	Solvent	30% – C12H27O4P
			70% – C12H26
	Equivis Oil	Oil	mostly alkane CnH2n+2
	Trash bin	Solids wastes	40% – PE tarpaulin/20% – PP wipes
			20% Latex gloves/10% – Tarlatane tape
			5% – Tissue/5% – Neoprene gloves
Large scale, low air change rate	Electrical cabinet	Solids	Mixture of electrical elements simplified to:
“DIVA”			50% – PVC
PICSEL_V1 EP2			25% – PE
			25% – PMMA

*30/70 corresponds to volume ratio of fuels in case of mixing.

Table 2 Physicochemical properties of emitted particles

Facility	Fuel	Vf (cm/s)	Nature	Dpp (nm)	Des (nm)	ηp (%)	TC (%)
Small scale, high air change rate “BANCO”	KIOWAGLASS	0.23	Fractal	39	—	4.3	5.4
		2.1				4.4
	LEXAN	0.23	Fractal	51	—	17.3	2.6
		2.1				18.3
	Electrical cable A	0.23	Fractal	40	—	0.5	4
		2.1		35	—	1.3	—
	Electrical cable B	0.23	Fractal	34	—	0.9	9
		2.1		25	—	2.1	9
	Electrical cableC	2.1	Coated fractal	48	296	13.3	9.6
	TBP/TPH (30/70)*	0.23	Coated fractal Compact	34	238	15.6	6.6
		2.1		31	234	14.7	5.3
	Equivis Oil	0.23	Coated fractal	38	249	6.3	1.5
		2.1		35	340	9.9	4.0
	Trash bin	0.23	Coated fractal	34	—	3.8	1.6
		2.1		32	—	10.1	3.6
Large scale, low air change rate “DIVA”	Electrical cabinet (PICSEL_V1)	0.23	Compact	—	222	3.7	>25
	Electrical cabinet (EP2)	0.14 to 1.4	Compact	—	226		>20

*30/70 corresponds to volume ratio of fuels in case of mixing.

FIG. 3. TEM micrographs of particles emitted by the thermal degradation of the studied fuels.

FIG. 4. Influence of the nature of the fuel on the clogging of HEPA filters at both filtration velocities.

FIG. 5. Comparison of predicted and experimental non-dimensional aeraulic resistances.

FIG. 6. Comparison between experiments and empirical relationship for full-scale fire.