Opinion by

The learned judge directed a verdict for plaintiff leaving to the jury only the amount of damages, on the view that the statute required the construction of a fire escape in exact conformity to the method and details prescribed, or in case of any variance, the approval of the proper municipal authorities as a mandatory requirement, the absence of which would create a liability to any person injured in consequence of a fire in the building irrespective of any question of negligence or proximate cause. The statute will not bear so-severe a construction.

The act of June 11, 1879, P. L. 128, required certain buildings to be provided with “ a permanent safe external means of escape therefrom in case of fire,” leaving the determination of the means to be adopted, to the individual owners, subject to the examination and approval of the fire commissioners or other proper officials.' A supplement was passed June 1, 1883, P. L. 50, and an amendment to the supplement on June 3,1885, P. L. 65, neither of which is material to the present case. On the same day however as this last act, June 3, 1885, P. L. 68, was passed an amendment to the act of 1879 which is the statutory law in force at the time of this accident. This act prescribes in great detail the nature and mode of construction of the external fire escape required, but also has a proviso that “ nothing herein contained shall prohibit any person .... from selecting and erecting any other and different device, design or instrument, being a permanent safe external means of escape, subject to the inspection and approval of the constituted authorities for that purpose.” The result of this act with its proviso is that while a design and mode of construction of fire escape are prescribed which if followed will absolutely exempt the owner from the penalties and liabilities of the act, yet he is left at liberty to erect one of a different kind at his own will but at his own risk that it shall prove “ permanent, safe, and external,” and that it shall be subject to the inspection and approval of the proper authorities.

. What then is the effect of a failure to obtain such approval ? The act of 1879 made it the duty of fire commissioners and other officials to examine and test fire escapes (the design and construction not being prescribed by the act), and if found satisfactory to grant a certificate of approval. The next sec*575tiop imposed certain penalties and liabilities for failure to comply with the act, which will be discussed later on. The effect of the failure to get a certificate of approval was thus left undefined. In the second act of 1885, P. L. 70, however, the provision for a certificate of approval was substantially reenacted and it was expressly added, “thereby relieving the party to whom such certificate is issued from the liabilities of fines, damages and imprisonment imposed by this act.” The effect of this clause does not admit of doubt. The certificate of approval is conclusive evidence of nonliability under the act, but it is not a mandatory requirement, and its absence creates no liability that would not otherwise arise from the facts. It is evidence only, and the sole effect of its absence is to put on the owner the burden of proof that he has complied with section first by building a fire escape in accordance with its directions, or under the proviso has made a permanent, safe, external escape which is substantially equivalent.

It follows that the evidence offered tending to show the erection of a proper and sufficient escape, as permitted by the proviso to section first of the act of 1885 should have been admitted. The evidence offered in the first assignment was not admissible, not for the reasons on which it was excluded, but because it was not of the required rank as the best evidence. The officer who issued the certificate would have been a competent witness as an expert, but his certificate is only admissible by force of the statute, and that extends only to certificates given on examination and test before the happening of the fire. The second, third and fourth assignments of error are sustained.

The seventh assignment must also be sustained. The defendant’s third point should have been affirmed. Section 8 of the act of 1885 gives the right of action in these words, “ every person .... neglecting or refusing to comply with the requirements of section one, in erecting said fire escapes shall be liable to a fine,” and be deemed guilty of a misdemeanor, etc. “ And in case of fire occurring in any of said buildings in the absence of such fire escape, approved by certificate of said officials, the said person or corporation shall be liable in an action for damages in case of death or personal injuries sustained in consequence of such fire breaking out in said building .... and s.ucb *576action for damages may be maintained by any person now authorized by law to sue, as in other cases of similar injuries.” The construction that this raises an absolute liability for all injuries on the happening of a fire, whether the absence of a fire escape had any connection with such injuries or not, would make the owner responsible for results of which his act was not the cause, or as in the present case, for acts of another over which he had no control. A construction which would make the law of such doubtful constitutionality should not be adopted unless the language renders it imperative. There is no such compulsion here. The last clause of the section quoted, that actions “ may be maintained by any person now authorized to sue, as in other cases of similar injuries,” shows clearly that what the legislature had in mind was the large and well known class of actions for death and injuries caused by negligence. This act added another to that class. The failure to build a fire escape was made an act of negligence for which a liability attached to the owner, but as in other cases of the same class, a liability only to those injured in consequence of such negligence. . There could be no better illustration of the wisdom and justice of this view, than the present case. The undisputed testimony is that the fire escape was safe, sufficient and effective when it was once reached. All the people on the fourth floor escaped by it uninjured. The difficulty was in the locking of the door that led to it on the third floor. The plaintiff got to this door in time, and had it been open as it should have been, she could have escaped without injury as did the others who came to- it, some of them after she did. The only proximate and effective cause of the injury was the locking of the door, and that according to the testimony of Taylor, the boss weaver, was done by him at the order of his employers the tenants. It was not the act of the defendant, or of any one over whom he had control or for whose actions he was responsible. The statute does not make him liable except for the consequences of his own act, and there was no evidence on which the jury should have been permitted to find that plaintiff’s injuries were the result of anything defendant did or omitted.

Judgment reversed.