sum timestamp result in hours

Select sum(age(rgat.rgat_tmencerramento, rgat.rgat_tmregistroatendimento))
from atendimentopublico.registro_atendimento rgat
inner join cadastro.localidade loca on loca.loca_id=rgat.loca_id
inner join atendimentopublico.solicitacao_tipo_especificacao step on step.step_id=rgat.step_id
where
date(rgat_tmregistroatendimento) between '2007-01-01' and '2007-12-31'
and rgat.step_id in (706,710,717,718,719,722,725,728,730,732,733,720,721,727,714,729)
and rgat.rgat_cdsituacao=2
and date(rgat_tmencerramento) between '2007-01-01' and '2007-12-31'
and rgat.rgat_tmencerramento > rgat.rgat_tmregistroatendimento
and rgat.loca_id=339
and rgat.rgat_id in
(20111305,
30102409,
30102096,
30097214,
30102396,
20057815,
20325895)
Result: 1 year 4 mons 88 days 51:42:00

I need help to view result query only in hours, the timestamp columns in bold above.
thanks
Paulo Moraes

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